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1. This young boy, sitting
studiously before his stereo microscope, belongs to a species
under development: micromounters. That is to say, those amateur
mineralogists who mount small specimens for study under the microscope. |
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2. Mineral collectors of a new type, they study micro
crystals of minerals, specially prepared for viewing at magnifications
of 10X to 80x.
3. The mineral, which is no larger than several millimetres,
is glued to a pedestal. Here, the pedestal is formed of a base
of balsa wood fastened to the bottom of a cubic plastic box,
of around two centimetres square. The assemblage constitutes
a "micromontage" in French, or "micromount"
in English.
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4. Almost all the micromounters
of the world are acquainted. A publication of the Baltimore Mineral
Society lists the names of thousands of adherents across the
five continents. The list of names and addresses, brought up
to date every two years, promotes regular correspondence and
exchanges between collectors. |
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5. Micromounting, long popular
in the United States, which has the majority of clubs, has gained
foot hold in Europe and France as this notice inviting participants
to come to Epinay sous Sénart on 16 and 17 April, 1983,
demonstrates. Since micromounters are often systematic collectors,
there is nothing astonishing in that this first meeting should
be organised conjointly. |
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6. This typewritten list records
the contents of the collection of Professor Orcel. It was found
in the drawers of the Museum of Natural History in Paris, where
Orcel was the curator of minerals. It dates from the nineteen
thirties, and indicates that even at that time, the terms ìmicromontureî
and ìmicromountî were in regular use in their current
meaning. |
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7. The Orcel collection consists
of 350 pieces in blackened cardboard boxes of 2 x 2.5 x 1.5 cm.
The pedestals are of painted wood (cork and poplar). One hundred
of them are accompanied by crystallographic cards, on which are
figured an original drawing, the indices of the faces, and the
values of the measured angles. |
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8. This type of ingenious
mount, using a rod of wood stuck in one of the sides of the box,
permits observation of the successive faces of the crystal by
simple rotation of the rod. |
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9. Besides the collection
of Orcel, the mineral gallery of the Natural History Museum holds
a small collection of one hundred mounts known as the "Lazard
Cahn" collection. It derives from exchanges made between
Orcel and this famous American collector, who, in a long career,
assembled thousands of samples now preserved at Yale University. |
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10. This round box belongs
to the collection of Des Cloizeaux, mineralogist and curator
of the mineral gallery at the end of the last century. It contains
micro samples which were used by the mineralogist for the study
of the optical properties of minerals. These boxes are contemporaneous
with the first American micromount boxes used by Rakestraw and
Fiss about 1880. |
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11. Among the oldest and most
illustrious specimens of the Museum are these diamond crystals
mounted by l'Abbé Hauy, using black wax and a pedestal
of painted wood. The label, in the hand of the founder of modern
crystallography, says: "Spherical diamond with an elongated
associate". This specimen dates from the beginning of the
19th century. |
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12. After this dip into the
past, here is a modern collection. Plastic is now largely employed
for the mounting of micromounts proper, but also for this type
of arrangement which holds 32 samples. |
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13. To generate a collection
of microminerals, it is necessary to begin by collecting them.
The primary instrument is incontestably the loupe, as indicated
in this shot of micromounters in full action. |
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14. A good basic loupe with
a magnifying power of 10x to 20x constitutes an indispensable
tool. A loupe of the type illustrated in the photo, firmly attached
by a cord passing around the neck to avoid loss, is an ideal
instrument. A microscope eyepiece with a large field of view
is also a possible solution. |
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15. There are also more specialized
means of observation such as this multiple function instrument
with the name EMOSCOPE. It can serve as a loupe, microscope,
or even telescope. |
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16. The remaining equipment required
for collecting is relatively classic. For example, a heavy crack
hammer is the tool for attacking hard rocks such as mineralized
basalts which harbour beautiful and rare zeolite species. |
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17. Chisels of various shapes
and forms such as this tile-laying chisel with an extra-wide
blade, or the small chisel with a cutting blade for delicate
operations, can prove useful for extracting mineralized plates. |
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18. As well as the regular packing material
currently used by amateurs (newspapers, paper towels, plastic
bags and boxes), it is useful to have a range of tubes and capsules
for small specimens. Gelatin capsules may be purchased at pharmacies. |
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19. Once the material has been collected,
one of the problems facing every collector is identification.
There is a multitude of criteria and methods, not always specific
or easy to use. We shall look at two techniques well adapted
to small specimens, for they need only minute samples. The first
is a dry test which relies on the crushing together of the sample
and a solid reactant in a dished plate. The coloration of the
mixture thus obtained gives an indication of the elements present. |
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20. Another method is to use wet microchemical
tests, in which the sample is taken into solution. A drop of
reactant is added, and the results observed under the microscope. |
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21. There appears in this way a precipitate
of remarkable micro crystals characteristic of the presence of
a chemical element in the mineral. For example, in this photo,
we see crystals characteristic of aluminium. |
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22. Before mounting microminerals, it
is necessary to reduce them to a size compatible with the boxes
in the collection, without excessive matrix. It is an operation
which requires delicate work, and above all, the use of apparatus
which produces a break which is clean, precise, and without too
much risk of deterioration of the sample being worked on. That
apparatus is a splitter, such as the double-toothed splitter
shown in the photograph. The shearing action is accomplished
by two chisel teeth placed on either side of the sample. One
of the teeth is fixed. The other is movable, and transmits pressure
resulting from the advance of a threaded rod turned by a wheel
or crank. The ensemble is mounted on a frame consisting of a
system of guides for ensuring the smoothest possible engagement
of the teeth. |
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23. To carry out certain finishing operations
(cutting, sawing, etc. . . ), one may also use tile-cutting nippers,
or a mini-drill with interchangeable heads, commonly found in
hardware or hobby shops. |
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24. To effect cleaning of many mineral
species under good conditions, one may use an ultrasonic bath
filled with water to which has been added a few drops of detergent.
There are baths of many sizes available, with prices based on
capacity. The illustrated 0.5 litre model was worth about 600
FF ($125) in 1983. |
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25. To hold micromounts, one ordinarily
uses plastic boxes of variable form and colour. They could, for
example, be cubic, from 1.5 to 2.5 cm on a side, and transparent.
They cost about 1/2 franc each. |
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26. The preferred boxes for micromounters,
however, are those in which at least the bottom, and sometimes
the entire box, is completely opaque generally black. A matte
black bottom allows most minerals good contrast for observation,
and results in a more aesthetic appearance. |
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27. There are multiple ways of producing
the pedestals for mounting. Besides mastic, or putty-like materials
(not recommended because they have long-term contamination effects)
it is necessary to mention balsa. This easily worked wood is
well known to model makers. It may be coloured or painted. It
is sold as round or square rods in various sizes. |
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28. To work balsa, we need a cutting instrument
such as a razor blade, scalpel, or hobby knife. |
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29. To make the specimen adhere to the
pedestal, we may use coloured glues such as Pattex Contact or
UHU Hart, or other special types. The point is to obtain rapid
adhesion, to prevent dripping or threads, and to develop a strong,
durable bond. |
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30. To attach the pedestal to the box,
one can use a self-sticking adhesive pad as a base. This can
be removed without leaving traces of glue if one wishes to transfer
specimens or to save on boxes. |
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31. Finally, to manipulate the specimens
safely, it is preferable to use tweezers of the type used by
philatelists, with either straight or curved tips. One can also
use ìXî tweezersóthat is, the type which
must be squeezed to open, but hold the specimen when released.
Dental probes or paper clips straightened out and pointed can
be used to clean or maintain the specimens while they are being
mounted. |
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32. How does one make a micromount from the material
described? Let's take an example:
33. Beginning with a clear plastic box, blacken the exterior
of the cover with cross strokes of a black felt pen.
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34. Turn over the cover, which will serve
as the bottom, and place on it a self-sticking adhesive pad to
act as the base of the pedestal. |
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35. Place a drop of glue on the pad, as well as on the
end of the piece of balsa which will serve as the pedestal .
36. Proceed to glue the specimen to the pedestal.
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37. Adjust the length of the pedestal in
such a manner that the mounted specimen enters the box without
difficulty. |
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38. With the aid of a pair of curved tweezers,
glue the mount to the previously prepared base, and verify that
it is in the correct position by checking with the stereo microscope
before the glue dries. |
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39. Using a pattern, trace the contours
of the insert on a piece of matte black paper or on a piece of
white paper which will be blackened afterwards. Cut the insert
out with scissors or with a paper punch. |
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40. After folding the insert, mount the
previously arranged specimen and pedestal in the centre of the
insert. |
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41. Place the whole in the box, obtaining
in this way, the same effect as having opaque plastic boxes,
or those painted on the inside. |
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42. For labelling, there are different
techniques, such as that of the rubber stamp giving an outline
to be filled in by hand. |
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43. Another method is to prepare a typewritten
label and photo-reduce it by about 50%. |
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44. There is also a label in the format
of the box, which gives a clean, legible presentation. |
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45. To avoid text overly cramped by the
size limitations of the label, it is possible to indicate nothing
on the box but the name of the species and a number. The number
refers to a card containing the relevant data. |
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46 On that card may be written all the
pertinent data giving details of the mineral, its associations,
specific characteristics, references, and place of origin. |
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47. For classifying and storing micromounts,
given their small size, one can often use commercial drawer sets,
such as this, available at office supply houses. These items
are, however, generally rather expensive. |
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48. One less costly method consists of
making trays of plywood, about 30 to 40 cm on a side, and 30
to 40 mm deep. |
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49. These trays may be used as drawers.
and may be placed in a cabinet constructed of 5 mm plywood with
brackets serving as slides. Such a cabinet may contain more than
2,000 specimens, already a good collection. |
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50. One might even go a little further
and construct a true piece of furniture which would go well with
the other furnishings of the house, such as this model in modern
style. |
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51. For preliminary classification, or
for transporting specimens for exchange, these plastic items
can contain a couple of dozen boxes. |
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52. The exchange or purchase of specimens
by correspondence is frequent among micromounters. Detailed lists
containing more than 100 species are common. They may even be
agreeably illustrated, as is this one from Italy. |
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53. Some lists are veritable catalogues
which must be constantly updated. Computer science comes to the
aid of the micromounter here, since with the aid of text processing
or database software one can rework lists with little effort. |
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54. Well packaged, samples of microminerals
circulate by post with ease. Small in size and in weight, they
cost little to send. Exchange becomes, therefore, an efficacious
means of developing a collection rapidly. |
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55. After having seen the different elements
which the micromount collection requires, it is necessary to
mention the last, but most important: the binocular or stereoscopic
microscope. There are a at least a dozen manufacturers and even
more models. High quality instruments with a wide range of magnifications,
good optics, a zoom system, and wide field of view are generally
costly. A complete outfit costs between 8,000 and 15,000 FF ($1,500
to 3,000). |
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56. Among that equipment, besides the optical
apparatus, it is necessary to think of choosing well adapted
lighting; for example a light source which transmits a cold light
obtained from a low voltage halogen bulb. The investment in a
stereo microscope is heavy, but it can be amortized over the
career of the collector. From the beginning, it is better to
wait a little and make some small sacrifices in equipping oneself
properly. |
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57. One of the most interesting aspects
of a collection is to fix on film the images which one sees through
the microscope. One may proceed by photomicrography to very large
magnifications thanks to a reflex camera mounted on one of the
eyepieces of the microscope. |
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58. One may also employ macro photography
thanks to a reflex camera mounted on a bellows with a lens of
20 or 50 mm focal length. This gives less magnification, which
permits work at greater depth of field, necessary when working
with three-dimensional objects such as crystals. From such a
system, we can get very good slides, or even practice projection
in 3-D with two slides taken at slightly different angles. This
technique is practised by Robert Vernet with great skill. It
is to him that we owe the following images, illustrating several
species which observation through the microscope aids greatly
in appreciating. |
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59. Here is a tridymite, magnified about
7.8 times. (Magnification: 7.8x) |
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60. A calcite from Villardonnel dans l'Aude.
(2.9x) |
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61. To continue the symphony in white,
a pharmacolite from Salsigne. (1.2x) |
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62. A classic piece: the association of
aurichalcite and hemimorphite from Mexico. (2.8x) |
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63. An acicular pyromorphite from St. Salvy.
(2.8x) |
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64. Here is an Australian gypsum crystal
with inclusions. (1.7x) |
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65. A striking wulfenite from Arizona.
(1.7x) |
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66. Some a well crystallized vanadinites
from Mibladen, Morocco. (3.7x) |
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67. A quartz with inclusions from Berbès,
Spain. (3.7x) |
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68 One sees astonishing things through
the stereoscopic microscope. |
69. If this activity attracts you, you may obtain more information
through the web page of the Association. Come to join us in the
bosom of l'Association Française de Microminéralogie.
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