Talc is an important industrial mineral. Its resistance to heat, electricity and acids make it an ideal surface for lab counter tops and electrical switchboards. It is also an important filler material for paints, rubber and insecticides. Even with all these uses, most people only know talc as the primary ingredient in talcum powder. Mineral specimens are not very common as it does not form very large crystals. However, it often replaces other minerals on an atom by atom basis and forms what are called pseudomorphs (false shape). The talc takes the form of the mineral it replaces. A specimen of what looks like milky quartz is quite a suprise when it not only has a soapy feel but can be scratched by a fingernail.

The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, gray to pink, commonly curved crystals, although it is usually massive. It has physical properties similar to those of the mineral calcite, but does not rapidly dissolve or effervesce (fizz) in dilute hydrochloric acid unless it is scratched or in powdered form.