Commercial gems are considered an elite group, singled out as being more "precious." The other stones comprising the gem kingdom are relegated to other, lesser categories such as "unusual," "semiprecious," "nonprecious," or "decorative" stones. This seems to imply that they are somehow less good. This may actually be the case; perhaps some catastrophic weak­ness such as softness, or easy cleavage, or even excessive rarity, eliminates the gem as serious competition for the select few. However, some of these stones may be just as valuable as their honored cousins, or may be useful for purposes to which the "precious" stones are unsuited.

Fortunately for gem lovers with collecting instincts there is a remarkable array of mineral species which can supply cut gems of some in­terest other than commercial value. Many of them are of transparent, faceting quality. Many more have some special desirable color or characteristic or scarcity which stimulates competition among collectors. With increas­ing demand for colored gems in the jewelry trade, there is a tendency for some of the odd gems to be promoted into commercial chan­nels. Sometimes a new supply of some exotic gem material creates an active market for it. Now and then the reverse process applies and a strong market interest in some particular gemstone stimulates prospecting and the de­velopment of new supplies.

There is yet another class of mineral ma­terials, such as rhodochrosite, malachite, and serpentine, that hold a place somewhere among the gemstones by virtue of their beauty when worked into objects of massive size. Unsuited for expensive jewelry and generally lacking in most of the important gem attributes, they often find ideal use as carvings or other art ob­jects or as decorative elements in the archi­tecture of buildings.

This summary of the "lesser" gemstones considers first those with appeal for collectors and, second, those of primarily ornamental value.