Techniques and tools used to convert "big ones" to "micromount size"
Dave Babulski, Ed.D.
("Tips and Trips", Vol. XXXI/7, July 2002, page 7.)
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.
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