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("Tips
and Trips", Vol. XXXIII/10, October 2004, page 10.)
"Organize and catalog your
collection"
Hello everyone. This month we
will
discuss some of the various ways that you can organize and catalog your
collection. It is sad to see a collection of beautiful mineral
micromounts
with no organization to the collection. When I first started out as a
micromounter
one of my mentors was a retired gentleman who had a fantastic
collection
of world class micromounts. But he had no formal catalog of his
collection.
He did have a label for each mount which helped a bit. However when you
consider that his collection had over 10,000 micromounts you can
imagine
the problem in trying to find a specific specimen. My point in relating
this story is to stress that a specimen label does not a catalog make.
Like mounting techniques I suspect that there are as many ways to
catalog
a collection as there are micromounters. Over the years I have tried a
number of ways of cataloging my own collection and to this day that
effort
continues to evolve as my collecting interests change. In its
basic
form a catalog for your micromount collection consists of two basic
parts:
(1) The label on the micromount itself, and (2) an external list of the
specimens in your collection. Let’s look at each of these
elements
individually:
The Label:
At a minimum the data you place
on
the micromount label should be the mineral name (spelled correctly, of
course), location where the specimen was found, and a catalog number.
Some
micromounters also record the chemical formula along with the mineral
name
and locality information. Since I hand letter my labels, that is a bit
much for me to put on my own micromount labels. Now I choose to go
against
convention and I mount in the lid of the micromount box. I use plastic
micromount boxes with lack lids. So when I mount the
“lid”
now becomes the “base”. I mount this way because I
use a home-brew gimbal stage with my microscope and this way just works
better for me. I place a self adhesive with dot in the upper right
corner
of the clear lid of the box. In that white dot I carefully write the
specimen
number. I choose to use a consecutive numbering system. Some collectors
use a Dana system and some use a combination of letters and numbers.
The
point here is to provide a way to quickly locate the specimen when it
is
stored in whatever drawer arrangement you use. Then using a larger
rectangular
label I write the mineral
name and locality information in
ink
on the label. This prepared label is attached to the top of the
micromount
box. On the bottom of the box, I use a smaller rectangular self
adhesive
label and enter the specimen number on this label. That way if the lid
and the base become separated I can always match them up. If the
specimen
is of special note, I sometimes place a colored adhesive dot in the
upper
left-hand corner of the box lid. (The same colored dot is placed in the
catalog as well) As a final step, I coat all the labels with a thin
coat
of Modge Podge. This is a decoupage fluid that you can buy at craft
stores.
What this coating does is prevents the adhesive from out-gassing
becoming
brittle and falling off over time. Now, we are not done yet!
The Catalog:
Currently I use sheets of college
ruled
notebook paper organized in a three-ring binder as my external catalog.
The specimen number is entered on the left side of the page and then
the
mineral name and detailed locality information is entered on the same
line
following the number. I used to enter the chemical formula but this got
to be too time consuming. If I need the mineral chemistry,
I’ll
look it up! I try and enter as much precise locality detail as I can.
For
me this adds to the enjoyment of the specimen. The internet is
invaluable
here. If you have not already seen it there is a site at
http://www.mindat.org
that has excellent locality detail for quite a few mineral species and
localities. Often if you enter the name of the mine, a wealth of
precise
locality data comes up. I have a second external catalog that lists the
specimen number and the chemical class of the specimen. For example I
have
a separate section for silicates, sulfides, arsenates, etc. Yea I know
it all sounds like a lot of work, but it is fun (well it is for me
anyway!)
and adds immeasurably to the enjoyment of a mineral collection. What
ever
technique you use to organize your collection, I encourage you catalog
your specimens, after all a specimen without a label and a catalog
entry
is just “a pretty rock”. Until next time, may all
your
skies be blue and all your vugs be crystal-filled.
("Tips
and Trips", Vol. XXXIII/7, July 2004, page 10.)
In this installment of the
Micromount
Corner, I want to share another way of enjoying mineral micromounts. We
know that one of the attractions of mineral micromounts is the
perfection
of crystal form and presence of subtle crystal sub-faces that are
typically
washed out as the crystal grows larger. There is a way that you
can
capture the subtlety and perfection of crystal form in mineral
micromounts
that also harkens back to a time before mineralogists had photography
as
a tool. This technique is called "Image Superposition". The
technique
takes a little practice but once mastered some amazing crystal drawings
can be created. In that time before photography, scientists used
a device called a "Camera Lucida" to draw what they saw in the
microscope.
A Camera Lucida (sometimes this device is called a “Drawing
Tube”)
is a mirror affixed to the microscope such that images reflected from
the
mirror are directed into the right stereomicroscope ocular. Meanwhile,
the left microscope ocular is directed through the microscope objective
at the specimen under observation. In the brain, the image from the
mirror
and the image from the specimen are superimposed on top of each other.
If a sheet of paper is placed under the mirror, the image of the
specimen
will appear to float on the surface of the paper. It is then a simple
matter
of following the outlines of the specimen to create a very accurate
drawing
of the specimen. Unfortunately a microscope fitted with a Camera
Lucida is not an inexpensive item. What I will share with you is a very
inexpensive way to create a "virtual" Camera Lucida by using one of the
oculars in a stereomicroscope, a sheet of paper and a good light
source.
This arrangement will enable you, with practice, to create some amazing
crystal drawings. The advantage of this technique is the ability to
capture
the crystal form with a very high degree of accuracy without the cost
of
photographic equipment. There are two basic optical arrangements for
stereomicroscopes,
the straight through ocular to objective arrangement and the tilted
ocular
through prisms to the objective arrangement. The technique is slightly
different depending on the optical arrangement in your scope.
Basically here is how it works:
- First you place the
specimen
on the microscope
stage and focus the scope.
- Second, position the
light
source so it
illuminates both the specimen and a sheet of paper placed on the table
on the right side of the scope. (NOTE: If your scope has tilted oculars
you will need to place the paper in a surface with the same tilt angle
as the oculars.) Position the paper as close to the microscope as you
can.
- Third, look through the
RIGHT
ocular with
your LEFT eye and look at the paper with your RIGHT eye.
[Note: This takes practice - ed.]
With
both eyes open, you will see the image of the specimen superimposed
on the paper. (Note that you may
need
to adjust the light source so that reflection of light from the paper
does
not wash out the image of the specimen.)
- Fourth, using a sharp
pencil,
carefully
trace the specimen outline on the paper.
Once you have the basic shapes
captured
on paper you can use both eyes with the microscope and refine your
drawing as required. You
can
enhance your micromount collection immeasurably with good crystal
drawings
of selected specimens. Minerals like Calcite, Wulfenite and Vanadinite
are examples of minerals that exhibit varied
crystal forms. Capturing these
varied
forms adds much enjoyment and appreciation to any micromount collection.
If you try this technique I
would like
to hear how it worked out for you.
("Tips
and Trips", Vol. XXXI/5, May 2002, page 5.)
Definitions
and Introductions
This is the first in a regular
series
of columns about mineral micromounting. This being the first column, a
few definitions and introductions are in order. So what is a micromount
anyway? There are two terms that we need to define first. These terms
are:
"Micro-mineral" and "micromount". The accepted definition of a
micro-mineral
is "any mineral specimen that requires a microscope to see clearly." By
this definition the mineral specimen could be the size of the head of a
pin or could be tiny crystals nestled in a vug in a fist sized host
rock.
If you have a collection of cabinet size mineral specimens you most
likely
also have micro-minerals as well. A micromount is defined as a
micro-mineral
which has been mounted in a small container, usually a box, to make
viewing
with a microscope much easier. Mineral micromounts offer the advantages
of small size, low cost, and perfection of crystal form. When minerals
are in micro form they often exhibit crystal forms that are washed out
as the crystals grow larger and more dominant crystal faces take over.
Another interesting aspect is that of the over 3500 known mineral
species,
only a few hundred crystallize in a large enough form to be viewed
without
magnification. With improvements in digital imaging technology it is
now
possible to image from the microscope with a digital camera and display
the image on a monitor screen. This is sort of like having a cabinet
specimen
"once removed!"
Now that we have some
definitions explained,
an introduction is in order. My name is Dave Babulski and I am the
chair
person of the Georgia Mineral Society Micromount section. I have been a
micromount collector for about 27 years. My collection numbers about
1500
cataloged specimens and growing. Although I teach electronics,
mechanics
and electro-mechanics in industry, my real passion is mineralogy. I
have
found a way to "scratch that itch" with the Georgia Mineral Heritage
Project.
Check with Georgia Mineral Society web page for an explanation of the
project.
The goal of the micromount
section is
to share experiences, specimens, techniques, etc. concerning micro
minerals.
If you have an interest in this area, I encourage you to join us in the
mineral world of the very small. In next months column we will talk
about
some of the equipment that is needed to enjoy mineral micromounting.
Until
then, may all the vugs you find be crystal filled.
( "Tips
and Trips", Vol. XXXI/6, June 2002, page 7.)
Equipment
required.
In the last column we learned
a bit
about the "what and why" of mineral micromounting. This month we will
discuss
some of the equipment required to participate in this aspect of mineral
collecting. The central piece of equipment is, of course, the
microscope.
In micromounting, the microscope type of choice is the stereo
microscope.
A stereo microscope is really two monocular microscopes placed side to
side such that there is an eyepiece for each eye. Each eyepiece looks
through
its own objective lens. In this way each eye sees the specimen from a
slightly
different angle. When the two images are combined in the brain, a
magnified 3D image appears. The type of instrument you should
select
can be summed up in three words: “Optics, Optics,
Optics”.
I highly recommend that you buy the best optics that you can afford.
The
least amount you can expect to pay for good optics is a little less
than
$200. Of course you can spend as much as $6,000 for high quality optics
with all the “whistles and bells”. I use an
inexpensive
fixed 20X stereomicroscope to initially examine specimens during the
mounting
process. I also use an Edmund Scientific trinocular stereo microscope
fitted
with a Nikon SLR camera for taking photomicrographs of micromounts. A
third
instrument, a Motic K4000 stereo microscope is fitted with a camera
lucida
for use in the art studio. This instrument is used when creating
paintings
of micro- minerals. (Both of these instruments are in the $1000 class)
A good starter microscope is the Edmund Scientific A81- 273. This is a
fixed 20X stereo microscope which can be had for about $195.00. (The
web
address for
Edmund Scientific is;
http://www.edmundoptics.com
Another low cost entry level stereo microscope is the Wolfe S10. This
is
another fixed 20X instrument. Additional accessories are available to
increase
the magnification. I do not recommend the higher magnifications as the
optics in the Wolfe instrument are a bit marginal. You will find that
for
most micromounts a magnification of 20X is sufficient. This microscope
is available from Carolina Scientific for about $135. The web address
for
Carolina is: http://www.carolina.com . Another important piece of
equipment for mineral micromounting is a good light source. A
good
place to start is an inexpensive halogen desk lamp. This has the
advantage
that the lamp can be used for other purposes as well. I have developed
an inexpensive color corrected miniature light source for use with the
microscope. An article describing construction of this light source is
being published in the July/August issue of Rocks and Minerals
magazine.
O.K. so now that you have the microscope and the light source, what
about
the minerals? Micromounts can be found in the same places that
cabinet
size specimens are found. You must just look more carefully. A good
hand
lens is indispensable when collecting in the field. Another source is
mineral
dealers. Most mineral dealers at shows will have flats of
thumbnail
size minerals. These are excellent sources for micromounts. In most
cases,
a good thumbnail can yield as many as six good micromounts. Of course
the
larger size specimens must be broken down to micromount size, but that
is a topic for the next column. Until next month, may all your vugs be
crystal filled.
( "Tips
and Trips", Vol. XXXI/7, July 2002, page 7.)
Techniques and
tools used to convert
"big ones" to "micromount size"
In the last column we
discussed techniques
for mounting microminerals to convert them to "micromounts". This month
we look at some basic techniques and tools used to convert "big ones"
to
"micromount size". Before we discuss techniques for breaking down
larger specimens to micromount size we need to note the leave it as it
is specimen. On occasion you will find a particularly fine crystal
group
within a much larger specimen. Typically the idea is to break down the
larger specimen to recover that fine crystal group. However, there are
times when doing so would destroy the very crystal group you are trying
to recover. In these cases it is best to leave it as it is. There is no
need to be enslaved by the little plastic micromount box! I have a
special
drawer in my own collection set aside just for the “leave it
as it is” specimens. Having said all this, you will find that
at least 90% of the time you will be able to safely break down the
specimen.
Now we need to define the term “breakdown”. Please
note that this term does NOT ALWAYS mean "smack it with a
hammer".
The brute force method is a sure way to destroy any delicate crystal
groups
that may be enclosed by the specimen matrix. The best way to break down
a larger specimen is to start with thumbnail size specimens to begin
with.
Of course the thumbnail collectors out there shudder when you talk
about
breaking down from thumbnail to micromount size. I know, I can hear you
saying, "O.K., Coach so just how do I get from "small
boulder”
to "thumbnail size"? The answer is by careful application of directed
impact
energy. A good set of tempered cold chisels can be used to concentrate
the impact of a hammer to a small area of a specimen. In this way you
can
more safely break down a larger specimen to thumbnail size pieces.
CAUTION:
When doing this SAFETY GLASSES are a necessity to protect your eyes
from
flying rock chips. Note this operation generates large amounts of
noise,
dust and vibration and as a result is best done outdoors. In my
backyard
I have installed a bench supported by a large, treated post driven into
the ground. The post serves to absorb the kinetic energy from hammer
blows.
Once a larger piece is broken down into smaller bits, they are brought
inside and broken down further with the rock trimmer. For this
additional
breakdown operation, I highly recommend you invest in a screw type rock
trimmer. These devices use a captured lead screw to move a hardened
steel
chisel toward a fixed hardened steel chisel in the base of the device.
The specimen to be broken down is placed between the two chisel points.
The lead screw is advanced until the specimen breaks. I recommend
placing
a blanket of thin foam sheeting in the bottom of the device to cushion
pieces of the specimen as they fall after being broken. My own rock
trimmer
is fastened inside an aluminum cake pan with the foam blanket covering
the bottom of the pan. The sides of the aluminum pan effectively catch
any stray pieces as the specimen is broken. I have been known to spend
up to 45 minutes just examining a specimen to determine the best way to
break it down to micromount size. It is a very satisfying feeling when
the specimen breaks down, properly exposing a new crystal filled vug or
parts into two perfect micromounts.
Expect to pay about $100 to
$400 for
a rock trimmer. I recommend spending the money to get a good device
that
will last a lifetime. Another useful tool is a pair of tile nippers.
These
can sometimes be used to trim smaller specimens. A small pair of
diagonal
cutters used for electronics work is also useful when trimming very
small
specimens. I do not recommend handling micromount specimens with
the
fingers. Two things happen here: 1) the finger oils from your hands are
slightly acidic and can, over time, damage delicate specimens and 2) It
is very difficult to avoid crushing very small and delicate specimens
when
handling them with your fingers. A good pair of forceps is highly
recommended.
(Forceps are just a large pair of tweezers. For most cases a pair of
tweezers
is too small to handle micromount specimens.) It will take a little
practice
to learn to use the forceps under the microscope. Another very
useful
tool is what I call a "glue dauber", which is nothing more than a
“Q-tip®”
with one of the cotton tips cut off. I carve the end of the stick to a
flat paddle shape. This is used to transfer a dab of glue to the
pedestal
when fastening the specimen in place. I keep a roll of toilet paper
handy
at the workbench to wipe off the glue dauber after each use. I must say
that the sight of the roll of toilet paper with its holder attached to
the front of the workbench does generate some interesting comments!
As you work with mineral
micromounts,
you will develop your own set of “special tools” in
addition to the usual set of tools. Before we leave this
discussion
we should discuss tools used to cut and shape the pedestal material. I
use two primary tools for this task; a Razor Saw and a number eleven
X-Acto®
hobby blade. The razor saw is used to cut cork pedestals to the correct
length. The X-Acto blade is used for any carving of the cork
pedestal.
Once you have the micromount safely mounted in the box, there is the
matter
of the label. There have to be as many different labeling schemes as
there
are micromounters. The label is important, as a specimen without a
label
is just another pretty rock! My collection is a working
collection
used to select specimens for conversion to micromineral paintings. Some
collectors collect specific species or divide their collection into
species
groups. Again whatever works for you is the correct way. I use a
sequential
numbering system with the specimen number placed on the top and bottom
of the box. I also place the name of the mineral on both the top and
bottom
of the box. This helps keep the two halves of the box together. There
are
several good books on micromounting that have some good suggestions
about
ways to label your specimens. I take the additional step of logging
each
specimen into a written sequentially numbered log. In this log I list
the
following for each entry: mineral name, chemical formula, specimen
location,
specimen number and drawer number, a description of the specimen under
the microscope, date secured and how obtained, and lastly a note about
fluorescence. I also keep a cross-referenced catalog arranged by
chemical
class and another by mineral name. All this work pays off for a working
collection.
Next month we will discuss
some sources
for micromount specimens. Until then, may the sky always be blue and
may
all the vugs you find be crystal filled.
Dave Babulski,
Micromount
Section Chair
( "Tips and Trips", Vol. XXXI/8,
August 2002,
page 7.)
"Sources
for mineral
micromounts."
This month we will look at
sources for
mineral micromounts. But first, some breaking news. For those of you
out
there who are looking for a good inexpensive microscope I have some
good
news. David Shannon, a mineral dealer in Arizona, is now a
U.S.
distributor for Motic microscopes. I use a Motic K400 myself. While
this
is a more expensive scope, this manufacturer makes several good
beginner
stereo microscopes. One word of caution however. The
advertisement
for Motic microscopes on page 281 of the latest issue of Rocks and
Minerals
magazine is misleading. The microscope shown in the picture is NOT the
Motic S-10-P model but is instead a more expensive model. I would
recommend
the Motic S-20-LO model. It is a few dollars more than the $139.50
amount
quoted in the ad, but the optics are first rate and well worth the few
extra dollars. Now back to the program already in progress. Where
do you go for mineral micromounts? The answer to this question is
really
twofold: (1) you can collect them yourself (more on this at a later
date)
and, (2) You can purchase specimens from a dealer. [ed. — or,
(3) someone can give them to you]. A quick look at the internet shows a
host of dealers who specialize in micromounts or who sell micromounts
as
a side line. I prefer to purchase thumbnail size specimens and break
them
down myself. This, for me, is part of the fun of micromounting.
You
will find that micromounts per se are a bit more expensive than if you
break down and mount them yourself. Another source for specimens is
mineral
dealers at gem and mineral shows. I have found that if you let the
dealer
know you are looking for micromount material they will often show you
specimens
they have in stock that are good micromount material. I have many a
specimen
in my own collection obtained in this way. Another guideline when
purchasing
specimens is purchase more than one! By purchasing more than one you
increase
your chances of several really first class mounts.
I make it a practice to purchase
at
least two of any given specimen. After you break them down to
micromount
size you may have as many as 8 to 10 micromount-size specimens.
Now
comes the hard part. Set the specimens aside for a few days and come
back
and examine them again. Set aside those that do not meet your mounting
requirements for trading or give away. Then set the selected
specimens
aside for another day or so and come back and re-select again. You
should
have the selection whittled down to 2 or 3 specimens. If you
don’t
cull at the beginning you will come back to those specimens that looked
so good early on and ask, “Now why did I keep this
again?”
I have digressed a bit, so back to the mineral dealers. For my money, I
find that David Shannon Minerals and Simkev Micromounts have the
greatest
selection and about the best value for the money. I used to buy a lot
of
specimens from Robert Eaton, but I have not seen ads for his business
in
the last few years so I assume that he is no longer in business. This
is
a shame because he would send you a thumbnail size specimen in a
micromount
box. There are two new dealers, ELEMENT 51 and The Complete
Micromounter
(Open for business in September 2002 says their web site). I have not
tried
them as yet, but if you have or if you have a favorite dealer, please
drop
me a line (my e-mail address is on the newsletter mast head) and I will
include the information in the Micromount Corner. One of the real
joys of micromounting for me is when the box of specimens comes in the
mail. The box is opened and there are all the specimens all neatly
wrapped
in paper like so many tiny gifts. The heart beats a bit faster as
each package is carefully unwrapped not knowing what new treasure
awaits
to be discovered.
May the sky be blue and all
the vugs
you find be crystal filled,
Dave Babulski,
Micromount
Section Chair
( "Tips and Trips", Vol. XXXI/10,
October
2002, page 8.)
Hello everyone. The Micromount
Corner
took the last month off as I was preparing for a micromount
symposium.
On August 31, 2002, my wife and I traveled to Hendersonville, North
Carolina
to participate in a meeting of micromounters in the Southeast. I
brought
some mineral art and was the featured speaker for the event. Now I have
been collecting micro mounts for over twenty years, and this was the
first
big micromount gathering that I have attended. Boy was it a
blast!
There were over 60 micromounters in attendance. I counted over thirty
microscopes
set up around the room. That was a sight! It was interesting as well to
note all the different types of stereo microscopes, everything from
some
genuine antiques to new state of the art scopes, all quite obviously
lovingly
cared for. The meeting took place in the Hendersonville Salvation Army
Building on the activity room main floor, so we had plenty of space. A
group of tables were set up in the middle of the room which were piled
high with specimens that were free for the taking (the give-away
table).
In addition to the vast array of stereo microscopes, there were almost
as many different mounting techniques on display. Most of the
micromounters
in attendance were very interested in trading specimens. These
folks
brought specimens loosely mounted in snap boxes or held in place with a
little mounting clay. It was a lot of fun to talk with other
micromounters,
who are a very friendly bunch indeed. There is an etiquette to a
micromount symposium. You should definitely bring specimens to give
away.
It is considered bad form to take from the give-away table without
putting
some specimens on the table for others to share. The old, trusty egg
carton
was the predominant specimen holder on the give-away table. When you
mount
for your own collection, set aside those extra specimens in a box and
then
bring them to the next get-together of micromounters. You would be
amazed
how many really nice specimens can be obtained from the give away table
or swapping with other collectors.
Most of the people in
attendance were
from the Southeast, however, one fellow came all the way from England
to
attend the symposium. Many new friendships were made along with a great
many warm memories.
May the sky be
blue and
all the vugs you find be crystal filled,
Dave Babulski, Micromount Section
Chair
QUALITATIVE
ANALYSIS FOR
THE MINERAL COLLECTOR
by Dr. David Babulski, Ed, D.,
Chair – Mineral Micromount Section, Georgia Mineral
Society
( "Tips and Trips", Vol. XXXI/12,
December
2002, page 9-11)
In these modern times when
mineralogists
routinely use X-ray diffraction, the electron microprobe, and
spectroscopic
techniques for the identification of a mineral species, qualitative
analysis
harkens back to a much simpler time. In the very early days of
mineralogy,
simple chemical methods were used to determine the presence of key
elements
in a mineral specimen. Information on the physical nature of a mineral
specimen, when combined with confirmation of elemental composition,
provided
positive identification of a mineral species. Chemical assay techniques
could then be employed to provide quantitative data on the composition
of a mineral specimen. For the mineral collector, the primary interest
is in positive identification of a mineral specimen. Clearly for the
vast
majority of cases physical characteristics of a mineral specimen can be
used to identify the mineral species. However, in some cases the use of
qualitative analytical techniques can provide positive identification
where
physical characteristics alone do not afford a positive identification.
In addition these qualitative analytical techniques can deepen an
understanding
of mineral chemistry, are a lot of fun and can provide an extra measure
of enjoyment to mineral collecting.
To better understand the
techniques
of qualitative analysis for minerals, we need to first take a trip back
in time to the mid 1700s in Sweden. In these early days of mineralogy,
minerals were largely described by physical characteristics alone. Many
scientists of the day began to apply the science of chemistry to the
study
of minerals. The Swedish chemist and mineralogist Baron Axel Fredric
Croenstedt
made a discovery that would change the young science of mineralogy
forever.
Croenstedt discovered that when intense heat was directed at a small
sample
of a mineral, certain elements in the mineral reacted in characteristic
ways. Temperatures in the range of 1500 to 2000°C could be obtained
with a simple device called a blowpipe. This device was nothing more
than
a curved tapering brass tube that was used to direct a blast of air
into
a candle or lamp flame. The extra oxygen supplied to the flame
increased
its temperature, and the movement of air through the flame changed its
shape and direction. Specific elements, when excited by the high flame
temperature, would color the flame in a way that was characteristic of
that element. In some cases, the vapors created and the oxides or
metallic
substances left behind were also characteristic of a specific element.
Artisans of the time had been using variations on the blowpipe for some
time to work with metals, but Croenstedt was the first to apply this
tool
to mineral analysis in a systematic way. The makers of stained glass
had
known for some time that certain metals could be introduced in small
amounts
into a glass melt to impart color to the glass. Borrowing a page from
the
stained glass makers, Croenstedt also discovered the ability of
specific
elements to impart a characteristic color to the glass created when
reactive
fluxes such as borax where heated in the blowpipe flame. Enough
information
was gained about minerals through this new blowpipe technique that
Cronstedt
felt justified in suggesting that minerals be classified not only
according
to their appearance but also according to their chemical composition.
Cronstedt
wrote a book detailing this new form of classification that was
published
in 1758. Although Cronstedt is primarily credited with the discovery of
the element nickel, he is also considered the father of systematic
blowpipe
analysis.
Now we move forward in time to
the
mid 1800s to Yale University in the United States. A giant in the
science
of mineralogy was a professor of Physics at Yale University, James
Dwight
Dana. Earlier discoveries in mineralogy were combined with considerable
research of his own and contributions from most notably G.V. Brush and
S.L. Penfield to create the Manual of Mineralogy published in 1843. In
this classic work, Dana combined an understanding of crystallography,
physical
characteristics of minerals, and mineral chemistry to produce a system
of mineral analysis and identification that is still used today. Brush
and Penfield also published a separate work on using the blowpipe in
the
analysis of minerals. This publication is considered the seminal work
on
the subject. James Dana’s son, Edward Salisbury Dana followed
in his father’s footsteps to publish Minerals and How to
Study
Them in 1895. This was the first book specifically targeted to the
non-professional.
This classic book has been updated by Hurlburt and Sharp and re- issued
in 1998 as Dana’s Minerals and How to Study Them. At a cost
of
only $40.00, it is highly recommended for the bookshelf of every
serious
student of mineralogy.
This presentation will examine
some
of the techniques used by mineralogists in the days before electronic
instrumentation
and how the mineral collector can enhance the study of minerals and
increase
the enjoyment of the mineral hobby by using some of these time honored
analytical techniques.
The most fundamental analytical
techniques
for minerals are their physical characteristics. It is important that a
complete understanding of the following mineral physical
characteristics
is obtained before moving on to more involved chemical techniques. Very
often a preliminary identification of a mineral species can be made
from
the physical characteristics alone, leaving chemical techniques to be
used
in a confirmatory role.
THE IMPORTANT PHYSICAL
CHARACTERISITCS
OF MINERALS:
Crystal Form Cleavage Parting
Fracture
Hardness Tenacity Specific Gravity Color Streak Luster Fluorescence
Taste
and Odor Magnetic Characteristics
A detailed discussion of these
physical
characteristics is beyond the scope of this presentation. Our purpose
here
is to examine some of the chemical techniques that can be used by the
mineral
collector. Perhaps the most readily available technique is Blowpipe
Analysis.
The equipment necessary for this technique is readily available, and it
contributes immensely to the enjoyment of the mineral hobby.
There are four groups of
blowpipe tests:
- Fusibility - This is a
measure of how easily
a small fragment of a mineral melts in the blowpipe flame.
- Flame Colors - These are
tests in which
a small amount of powdered mineral is introduced into the flame and the
resulting flame color observed. Only a few of the elements so excited
will
yield a flame color.
- Bead Tests - These are
tests
in which a
small amount of powdered mineral is caused to react in the blowpipe
flame
with a molten reactive flux of borax or sodium ammonium phosphate.
Specific
elements will impart a characteristic color to the resulting glass
bead.
- Charcoal Block Tests - In
these tests a
small amount of powdered mineral is roasted in a small depression in
the
charcoal block. Some minerals will produce sublimates on the block,
specific
odors, characteristic oxides, or metal residues.
Although brass blowpipes are
readily available,
the advent of the small fine point butane torch has begun to displace
the
classical blowpipe. This is particularly the case with field mineral
exploration
and prospectors.
To demonstrate the use of the
blowpipe,
I will recount the analysis of a mineral specimen found at a
construction
site just off of Peachtree Industrial Boulevard in Duluth, Georgia. The
construction site had cut into the northeastern flank of the Wolf Creek
Formation. The host rock was a graphite-bearing schist with pyrite and
minor chalcopyrite found in the upper portion of the exposure. The
mineral
occurred filling a fracture cutting across the fabric of the host rock.
The physical characteristics
of the
mineral are as follows:
Color: Pale sky blue Crystal
form:
Botryoidal
Hardness: 5.5 to 6 Streak: White
None
Parting: None Fracture: Pronounced conchoidal
The mineral specimen was
tested for
fusibility and was subjected to a borax bead test and charcoal block
test.
Before we begin a word about safety is in order. When conducting any of
these mineral tests, always wear SAFETY GLASSES. WARNING: Always
conduct
tests involving open flame in a fireproof area and always have a fire
extinguisher
in the immediate area.
a. Fusibility: The
mineral
was found to be infusible in the blowpipe flame. Flame color observed:
light green color, very pale and only present for a brief time. These
are
suggestive of the element copper.
A small sample of the mineral
was pulverized
and ground to a fine powder with a mortar and pestle. A small amount of
this powdered mineral is mixed with distilled water to make a paste.
This
is placed into a small divot carved on one end of a charcoal block. The
mineral is heated very strongly with the blowpipe oxidizing flame. This
action removes any volatile compounds and converts any metal elements
present
to oxides. The next series of tests are bead tests that respond best to
oxides of metallic elements.
A small amount of the powdered
mineral
roasted on the charcoal block is attached to the platinum loop by first
moistening the loop with HCl (dilute hydrochloric acid) and then
reintroduced
into the blowpipe flame and any flame color was observed. Flame color
observed:
A deep azure blue color for a brief period. This test again suggested
the
presence of the element copper in the specimen.
b. Borax Bead Test: A clean
platinum
loop was heated in the blowpipe flame and then dipped into powdered
borax
and reintroduced in to the flame. This was repeated until a clear glass
bead was present in the loop. The bead was re-heated and a small amount
of powdered mineral previously roasted on the charcoal block was
attached
to the molten bead. This was then re- heated to allow the borax flux to
react with the mineral.
Oxidizing Flame: Bead,Hot: Pale
green
Bead Cold: Pale blue Reducing Flame: Bead Hot: Colorless Bead Cold:
Slightly
Reddish
It is important to know the
difference
between the oxidizing and reducing portions of the blowpipe flame. The
oxidizing portion is just outside of the hottest part of flame, while
the
reducing flame is just outside the blue cone in the flame. These beads
tests again strongly indicated the presence of the element copper in
the
specimen.
c. Charcoal Block Test:
In this test, a small amount of
the
powdered mineral was roasted with the blowpipe flame in a small
depression
in a charcoal block. Any fumes, sublimates, or residue were observed.
Since
the blowpipe bead tests were positive for copper, the mineral will be
roasted
on the block and then moistened with HCl, and then re-treated with the
flame. The chloride ion in HCl will combine with any copper present to
create copper chloride. A bright deep azure blue flame color is
characteristic
of copper chloride and is a positive test for Copper. Upon heating the
treated sample with the blowpipe flame, a bright azure blue flame color
was observed. Note that this is essentially the same result as the
flame
test conducted earlier. So once again we have a positive test for the
element
copper.
The results of blowpipe tests
show
a strong indication for the presence of the element copper in the
mineral
specimen. Based on this information and observations of its physical
characteristics
I tentatively identified the mineral specimen as chrysocolla. Now that
we have a good idea of some chemical elements in the mineral and a
tentative
identification, the next step is to use some wet chemical tests to
confirm
our observations. A number of entrepreneurs have developed mineral
testing
“kits” for the mineral prospector and mineral
collector.
These kits are relatively inexpensive and include enough materials for
quite a few tests. A note about chemicals is in order here. In
today’s
world, most chemical supply houses will not sell chemicals to an
individual
not connected with an education institution or industry. This is
particularly
true for acids used in mineral analysis. Hydrochloric acid can be
purchased
from most building supply stores as muriatic acid for swimming pools.
In
most cases this is the only acid you will need, and then it should be
in
dilute form. A word of WARNING here; When diluting acid, always add
acid
to the water. NEVER add water to the acid. Adding water to acid will
cause
the water to react violently resulting in splashing and acid burns. You
should use a solution that is 50% hydrochloric acid and 50% distilled
water.
Nitric acid and sulfuric acid are difficult to obtain as just a private
citizen. If you can find a source for these acids, try to obtain them
in
dilute form. You will not need very much as there are only a few tests
that require these two acids. Acids are dangerous chemicals and MUST be
handled with great care. Wear protective clothing and gloves when
working
with acids or other chemicals. Make sure to wash your hands after
performing
tests in which chemicals are used.
When conducting wet chemical
tests for
determinative mineralogy, two approaches are commonly used. The first
approach
is to use a testing protocol that looks for the presence of one or more
of the forty elements commonly found in minerals. In this approach, a
series
of 36 tests are performed and the results of each test recorded. The
data
is then collected and a determination of elements present is made.
Typically,
the tests must be conducted in a specific order because the results of
each test are used in conducting the next test. It should be noted here
that you do not need large amounts of specimen material for this
testing
protocol. Each test uses a tiny amount of specimen material. This is
the
approach used with some of the testing "kits" found in today's market
place.
The second approach is to use selective tests indicated by the physical
characteristics of the mineral, initial blowpipe observations and its
mineral
associations. For our example we used the second approach. Since
we have tentatively identified the mineral as chrysocolla, we will look
for the presence of silica and copper with the wet chemical tests.
TEST FOR SILICA:
Since we know that chrysocolla is
a
Hydrated copper silicate (CuSiO3 – nH2O) a test for the
presence
of silica was performed: A small amount of the powdered mineral
was
mixed with 5 parts of sodium carbonate and roasted on the charcoal
block.
The fused mass was pulverized and ground to a powder. A small amount of
this powder was placed in the bottom of a test tube to which 2 cc of
dilute
hydrochloric acid (HCl) was added. The solution was heated to just
boiling
and poured into an evaporation dish. As the solution evaporated, a bit
of insoluble gelatinous material was left behind. The results of this
test
are characteristic for silica.
TEST FOR COPPER:
A small amount of the powdered
mineral
was placed in the bottom of a test tube and about 2 cc of dilute
hydrochloric
acid (HCl) was added. After a few minutes the solution was a pale green
color. The addition of 6 cc of ammonia changes the color of the
solution
to blue. This is a positive test for copper. Since both tests are
positive, we have confirmed the mineral identification as chrysocolla.
The mineral specimen is a little harder than is typically the case for
chrysocolla. This specimen is most probably tending more toward a
copper-
bearing Chalcedony than true chrysocolla. Examination of a number of
individual
specimens showed an apparent gradation from chalcedony to
copper-bearing
chalcedony to true chrysocolla. Not only did we positively identify the
mineral species, we have had a lot of fun and enjoyment in the process.
For the mineral collector, using the analytical techniques of old can
provide
another rewarding aspect to mineral collecting.
POSTSCRIPT:
This specimen is one of the few
reported
occurrences of the mineral chrysocolla in Gwinnett County, Georgia. The
speculation is that the copper is derived from the dissolution of the
chalcopyrite
found in the host rocks. The silica most likely derives from
dissolution
of silicates in the host rock. Microscope examination shows tiny gypsum
crystals on top of some of the Chrysocolla. Oxidation of both Pyrite
and
Chalcopyrite found in the formation may have provided source material
for
the gypsum crystals.
SOURCES OF MATERIALS:
Mineral Test Kit: A Field test
kit
is available for $122.50 from:
Delos Toole Gold Books 5564 Lloyd
CT
SE Salem, Oregon 97301
This is a fairly complete kit.
However,
I recommend purchasing separately a good brass blowpipe, charcoal
blocks
and platinum wire for bead tests, as those supplied in this kit are not
very useful. Acids, hydrochloric, nitric and sulfuric and the base
ammonia
are listed as reagents but are not included in the kit. (Dropper
bottles
for these reagents are included however.) No information is given on
the
recommended strength of the reagents. Some chemicals are supplied in
powder
form to be reconstituted with distilled water. Instructions are
provided
for purchase of additional powdered chemicals. The kit also includes a
copy of “Duke’s Short Course in Prospecting and
Mineral
Identification”. This is a multi-step testing protocol using
the blowpipe and chemical tests. This qualitative testing protocol is
well
written; it emphasizes performing the tests under field conditions.
Mineral Testing Supplies: A good
brass
blowpipe, charcoal blocks, materials for borax bead tests, and other
supplies,
other than chemicals, can be purchased from:
Miners Incorporated 35 Pollock
Road
P.O. Box 1301 Riggins, Idaho 83530 – 1301
(ed: A book with a good
discussion
of these chemical tests is: A Field Guide to Rocks and Minerals by
Frederick
H. Pough.)
BIBLIOGRAPHY:
Books:
Anthony, L.M., Introductory Prospecting and Mining, 1997,
Mining
and Petroleum Training Service, University of Alaska, Anchorage, 155
Smithway,
Suite 101, Soldotna, AK 99669
This book is primarily a basic primer on prospecting and
mining
with a very nicely written "Summary of Chemical and Blowtorch Tests for
the more Important Elements". The testing protocol used here is geared
toward individual tests rather than a series of interdependent tests.
Brush, G.J, Penfield, S.L., Manual of Determinative Mineralogy
with
an Introduction on Blowpipe Analysis, 16th Edition, 1926, John Wiley
and
Sons, London
This is the seminal book on the subject of Blowpipe Analysis.
The
book is long out of print but can be found in most university libraries.
Hurlbut, S. and Sharp, W.E., Dana’s Minerals and How
to
Study Them, 4th Edition, 1998, John Wiley and Sons, Inc., New York
(ISBN
# 0-471- 15677-9)
This is one of the best reference works for the mineral
collector.
Most bookstores can order this book for you. Be prepared to wait a few
weeks as the demand for this book is not great. Most book distributors
must special order the book.
Lewis, J.V., Hawkins, A.C., A Manual of Determinative
Mineralogy
with Tables, Fourth edition, 1931, John Wiley and Sons, New York
The fold-out tables in this book are a fascinating look back
at
a time when blowpipe and wet chemical analysis were the primary tools
of
the mineralogist. This is another book long out of print. You should be
able to find a copy at a university library or on the used and rare
book
market.
LaRune, T.D., Rockpecker, A Mineral Prospectors Primer, 1993,
Skill
Quest Co., 675 Fairview Drive, #246, Carson City, Nevada 89701 (ISBN #
1-886499-00-4)
This appears to be a self-published book composed of four
parts.
The first part deals with basic geology and mineralogy with an emphasis
on gold prospecting. The second part deals with prospecting techniques
for gold. The third part discusses physical identification of minerals,
and Part four deals with blowpipe and wet chemical tests for minerals.
This fourth section is difficult to use. Many of the test procedures
use
a complex testing protocol with a confusing scheme of reference to
previous
tests. The tes ting protocol seems to be geared more toward the gold
prospector.
Madonna, J.A., Ph.D., A Prospector's Guide to The Physical and
Chemical
Identification of Minerals, 1997, Alaskan Prospectors Publishing, 504
College
Road, Fairbanks, Alaska.
This is a clearly written spiral-bound booklet that details
physical
Identification and wet chemical and blowpipe tests for the elements
found
in the common ore minerals. Also included is a simple method for the
determination
of specific gravity.
Internet Resources
http://webmineral.com
This site offers a complete mineral data base and some
excellent
information on blowpipe tests. Of particular interest, is a color borax
bead chart.
http://www.stonetrails.com/testing/flame.htm
A very nice site on flame tests for minerals.
http://www.rockhounds.com
This is the site for Bob's Rock Shop. This is one of the
better
internet sites for mineral collectors. This site also includes
information
on flame tests for minerals.
(
"Tips and Trips", Volume
XXXII/One , January 2003, Page 8)
A
new type of micromount box
and
Some notes on
micro-minerals.
This
month we will look at a number of things
relating to mineral micromounts. First,
I have found a new type of
micromount
box (Well it is new to me at least!)
available from David Shannon (Dec. 1/2004). David
was a mineral dealer from the Mesa, Arizona
area. His wife still offers a standard slip fit micromount
box with either a black lid or a black
base. These are wonderful in that it eliminates
the need to paint the inside of the
box or the lid. One needs only to paint
the support pedestal for the mineral specimen.
Another plus on these boxes is
the lack of mold flashing. On some micromount boxes you must
trim off the little rough bits where the box was attached to the
plastic mold. I have found that the Super Glue brand model/hobby
cement made by the Pacer Corporation (available at Michael’s
Craft Stores) works well to attach cork pedestals to the inside
of the black plastic lid or box. The address for David Shannon
Minerals is: 6649 E. Rustic Drive, Mesa, Arizona 84215.
A catalog of minerals and supplies is available from David Shannon
Minerals for $2.50. Ask for list # 352.
Some
notes on micro-minerals. One of the most difficult minerals to
get in good small crystals is Cinnabar. There is a lot ofmassive
material available, but good cinnabar crystals are hard to come
by. I just received a shipment of thumbnail size mineral specimens
from David Shannon Minerals and one that I ordered was
Cinnabar from the Dewey Mine near the geysers in Sonoma County,
California. Excellent, tiny well formed cinnabar crystals and
crystal groups were found in abundance on the specimens. Cinnabar
is a very attractive bright red mineral (essentially HgS) that
makes a handsome addition to any mineral collection. Another
interesting acquisition from David Shannon Minerals are several
specimens of cuprian Adamite (a basic zinc arsenate Zn2(AsO4)(OH)).
These are micromount size, pretty, light green adamite
in classical adamite crystal habit. I might add that the cost
of these specimens is really quite reasonable. Next
month we will begin a detailed description of how to make "pin
mounts". These are very tiny micro minerals mounted on the head
of a pin. Sounds difficult, but it really is an easy mount to make
and it presents a very attractive and neat micromountpackage.
And now (drum roll please), I want to announce a new web
site for mineral art. As many of you know your intrepid micromount
chair person is also a mineral artist. I specialize in watercolor
paintings of micro minerals painted from the microscope.
I have put together a small web site called “Crystal Pocket
Studios” to display the art. The URL for the web site
is: http://home.attbi.com/~d.babulski/.
Stop by on the web and let me
know what you think of the art.
Well that is about it for this month.
(
"Tips and Trips", Volume
XXXV/Three, March 2006, Pages
9-11)
THE MICROMOUNT CORNER
Dr. David Babulski, Ed.D.
GMS Chair, Micromount Section
MAKING A BABULSKI-STYLE MICROMOUNT
Greetings everyone, I have a special Micromount Corner for you
this
month. I will describe how I create my special Babulski-Style mineral
micromounts.
Unlike conventional practice I do not mount in the
“box”
but rather in the “lid” of the box. I use the black
base type slip fit micromount boxes. Now you may ask, just why go
against
the conventional wisdom and mount in the lid of the box? The answer to
that question deals with the home brew gimbal microscope mechanical
stage
I invented. I have always thought it a shame that much of a mineral
micromount
specimen was not available for viewing because much of it was hidden by
the sides of the box. By mounting in the lid of the box and then using
the gimbal mechanical stage, I can view the specimen through 270
degrees
of rotation. Thus allowing examination of areas of a specimen that
would
otherwise remain hidden by the conventional “In the
box”
type mount. For our example, I will show mounting of a Spessartine
garnet
specimen from Yunling, Zhangzhou Fujiian, China.

Photograph 1: Parts of the Micromount
In the photograph shown above, we see the micromount
box, a cork
that has been cut to size to both support the specimen and allow it to
fit inside the box, the mineral specimen and the original specimen
label.
I prefer to mount my specimens in pedestals in the
“lid”
of the box. There are some who prefer to temporarily mount the specimen
using tacky putty. There are no absolutes here so what ever technique
works
for you is the best one. Because I use my gimbal mechanical stage when
examining specimens, having the specimen permanently mounted on a
pedestal
allows positioning from horizontal to vertical in the stage without
having
the specimen fall off of the mount. For most of my micromounts I use
small
corks in sizes 0, 00, 000 and 0000 as the pedestals. I use a hobby
razor
saw to cut the cork to the proper length. The specimen is temporarily
placed
on top of the prepared pedestal and a micromount box is test fitted
over
this assembly to ensure that the box will not hit the top of the
specimen.
The specimen is then removed and, as shown in Figure 2 below,
glued
into place in the lid of the box. I use a solvent based adhesive
called:
Super Glue Corporation Model/Hobby Cement made by Pacer Technology.
This
adhesive does contain the solvent methyl ethyl ketone (MEK) so it must
be used in a well ventilated area. (MEK is considered to be a hazardous
substance - editor.)
CAUTION: Use only a small dab of adhesive, using too much will leave
an unsightly blob of dried adhesive at the base of the pedestal.

Photograph 2: Gluing the Pedestal in Place
Using a pair of forceps place the pedestal in place in the lid
and move
the pedestal in a very small circular motion; this helps the adhesive
bond
to the plastic of the lid. The next step is to paint the outside
surface of the pedestal flat black so it blends in with the black of
the
lid as shown in Photograph 3 below. This ensures that the
pedestal
will not distract from the specimen when it is viewed under the
microscope.
Use care to not get paint on the top gluing surface of the pedestal. I
use Model Master Flat Back enamel paint for this purpose. Testors #1156
Brush Cleaner works well to wash out the brush after painting the
pedestal.
After the paint has dried overnight you are ready to continue making
the
mount. The next step is to mount the specimen to the pedestal.

Photograph 3: Painting the Pedestal Flat Black
I use a Q-tip® with the cotton part cut-off and a flat spot
carved
on the end as a “glue stick”. I squeeze a bit of
the
adhesive out on the glue stick and place it on the top gluing surface
of
the pedestal. This is a trial and error procedure.

Photograph 4: Mounting the specimen
If you use too much adhesive it oozes out and dries to an ugly
mass
that detracts from the beauty of the specimen. If you use too little
adhesive,
the specimen can detach from the pedestal. Next you carefully position
the specimen on top of the pedestal, as shown in Photograph 4 above.
Allow the adhesive to fully cure, about six hours. Then, under the
microscope,
I use a very small brush and the flat black enamel paint to cover any
exposed
pedestal or dried adhesive. When the transparent portion of the box is
fitted to the lid which is now the base, you have a very attractive
micromount
as shown in Photograph 5 below.

Photograph 5: The Completed Micromount
All that remains is to attach the labels. Make sure to label
each micromount
as they are completed. Now the completed mount is ready to enter into
the
catalog and the collection. As a side note, you can preserve your
labels
by coating them with a thin layer of Mod Podge. This is a decoupage
medium
that you can buy at any craft store. Once dried the Mod Podge
forms
a water proof plastic shield over the labels keeping them clean and
preventing
the label adhesive from de-gassing and drying out. This causes the
label
to come off the box. As mentioned earlier in this column, I use a
gimbal mechanical stage of my own design which allows me to position a
specimen at any angle and have it held there for an extended period of
time. I have my microscope fitted to a X/Y positioning device. (A
surplus
X/Y drill press vise) which moves the microscope in linear X and Y
directions.
The gimbal stage allows me to move the specimen in azimuth and
rotational
X and Y. Photograph 6 below, shows the specimen fitted in the
Gimbal
stage.

Photograph 6: Specimen in the Gimbal Stage
To date my micromount collection numbers over 2000 specimens
most mounted
in “Babulski Style” mounts. I would like to hear
about
how you mount your specimens. You can reach me via e-mail at
d.babulski@comcast.net.
(
"Tips and Trips", Volume
XXXV/Six, June 2006, Pages 13-14)
MAKING 3D
PHOTOMICROGRAPHS
I
have been interested in 3D imaging for quite a long time and recently
have begun experimenting with 3D imaging through the microscope. A
growing area of experimentation on the part of 3D imaging hobbyists is
creating 3D images form the microscope. There is abundant information
about 3D imaging and 3D photography on the internet. I would
suggest
that you look at some of these interesting web sites before
experimenting on your own. (A number of these web sites are listed at
the end of this special report.)
A stereo microscope yields two
images separated by the distance between our two eyes. Through the
stereo microscope each eye sees a slightly different view of the
specimen. When these two slightly shifted images are combined in the
brain the sensation of a 3D image is created. The goal of 3D
photomicrographs is to create the
illusion of a 3D image without
using the stereo microscope. After much experimentation, I have
found a relatively easy way to create 3D photomicrographs of mineral
micromounts. The technique I use employs the Babulski gimbal mechanical
stage with the microscope used to take the photomicrographs. The gimbal
stage makes the task of
positioning the specimen for 3D imaging very
easy. The idea behind 3D imaging is to create two images shifted in
position, as each of our two eyes would see them through the
stereomicroscope. To see the 3D effect, these two photographic images
are placed next to each other and held at reading distance (About arms
length). Looking at
the junction between the two images you cross
your eyes and then let your eyes relax (This takes a little practice so
be patient). You will see a third image appear between the two
photographs, this third image will appear in 3D!
To create a 3D
photomicrograph using the Babulski gimbal stage, you first center the
specimen and note the position of the inner gimbal ring. Then you
rotate the inner gimbal ring 2.5 degrees to the right and make a
photographic exposure. Note that this is the “Right Side” image. Then
rotate the inner gimbal ring 5 degrees to the left and make
another photographic exposure. Note that is is the “Left Side” image.
Using the gimbal stage makes the process very easy.
A number of major factors must be kept in mind when creating 3D
photomicrographs. These major factors are:
1. The linear alignment of the
two images is critical. Care must be taken to move the stage or the
microscope in linear X or Y directions to keep the specimen in the
correct orientation between
the two photographic exposures.
2. Lighting between the two exposures must be as close to the same as
possible. This can be a bit
tricky particularly if the specimen position was moved both in the
linear and gimbal rotation
directions.
3. Focus must also be the same between the two exposures. I have found
that selecting several
key areas of the specimen as focus markers helps maintain overall image
focus between the
two exposures.
4. It is critical to note which exposure is image “right” which is
image “left”. When viewing the
two images to create the 3D effect, the left image must be on the left
and the right on the
right side. If the images are reversed, the 3D effect will not appear.
Figure
1 shown below is a stereo pair taken through the microscope with the
Babulski gimbal stage technique. The images are four second exposures
on Kodak ASA 400 color print film at a magnification of 25X.
Figure 1: Stereo Image pair of Mixite with Malachite and
Azurite from the Carisso Mine, Tintic District, Utah.
Figure
2 shown below is a stereo pair of Vanadinite taken through the
microscope with the Babulski gimbal stage technique. The images are
four second exposures on Kodak ASA 400 color print film at a
magnification of 25X.
Figure 2: Stereo Image pair
of Vanadinite from the Ford
Mine, Tucson Wash, Pinal County, Arizona
Having
the ability to view 3D images of some favorite mineral micromounts
without the stereo microscope offers another way to enjoy mineral
micromounting.
Internet References:
www.mineralarts.com/stereo/micro.html
www.ray3d.com
www.3d-web.com
www.3d2di4.com
For
more information on the Babulski Gimbal Mechanical Microscope Stage,
see Rocks and Minerals magazine (73:06), Nov./Dec., 1998
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