Waco Gem and Mineral Club, Waco, Tx

16.3 Collecting Preparing and Storing Microminerals

 

16.3: Collecting, Preparing, and Storing Microminerals

Collecting microminerals. What does a chunk of rotting granite shedding flakes of mica, quartz, and feldspar have in common with a freshly cracked geode with interior crystals speckled with black dots? On close inspection, both may yield perfect microminerals. In collecting microminerals, kids need to dive in nose-first and really get up-close-and-personal with the rocks. It‘s not enough to scan the ground from above. Kids need to get on hands and knees or even their bellies when searching through gravel or over matrix likely to hold tiny crystals, and they‘ll definitely need to bring their 10X or 20X loupes to look closely at what they spy. I‘ve found perfect little "Pecos diamond" quartz crystals while lying on the ground, picking through the sandy rubble of an ant hill in New Mexico.

Preparing microminerals. Preparing microminerals involves trimming away matrix, very carefully, very slowly, just a little at a time. Basic supplies include hammers and small chisels (along with eye protection), nippers and/or special vice-like rock trimmers, a small rock saw, Dremel-type grinding and cutting bits, dental picks, pointed-nose pliers, tweezers of various sorts, glue, and a bench magnifier that allows for hands-free work or even better, a binocular stereomicroscope, commonly called a dissecting microscope.

Storing microminerals. Microminerals are usually permanently glued into a protective container and are then referred to as micromounts. Micromount boxes with a black bottom and clear, snap-on lid can be purchased from mineral supply stores, or you can use those small plastic boxes with snap-on magnifier lids. There are many sophisticated techniques for gluing microminerals onto tiny rods and mounting them in display boxes. But for kids just beginning, it‘s probably best to use pedestals of tiny corks painted black. They‘re can be handled more easily, both for gluing on the specimen and for positioning and gluing the pedestal into the box. Trim down the pedestal to keep the top of a mineral specimen just under the upper lip of the box so the lid never comes in contact with the mineral. If possible, the pedestal should not be visible beneath the mineral when viewed from above. Have kids practice with less desirable specimens until they acquire patience and skill at gluing and positioning with tweezers. For practice, they should start with larger specimens with flat bottoms to glue to larger pedestals. Great attention is needed, with a steady hand, to place and glue a micromineral to a pedestal. Also, work should be done on a tray under good lighting so tiny specimens don‘t get dropped and lost.

Sauktown Sales (Mill Creek, Indiana) specializes in micromount specimens and supplies. On their web site, they provide not only supplies but much useful information and links to nearly two dozen web sites related to micromounts. Although pitched toward an adult audience, a couple reference books and a web site also provide fine information for you to consult in working with kids on this activity:

Milton Speckel, The Complete Guide to Micromounts (1965, 1980; now out of print?)

Quintin Wight, The Complete Book of Micromounting (1993). Available through the Mineralogical Record.

'The Micromount Corner

Note: Kids can use this activity to satisfy requirements toward earning the Collecting badge simultaneously (Activity 5.1).