near DeKalb, St. Lawrence County, New York. When cut brilliant, diopside makes a very attractive stone and resembles green tourmaline,
DIOPTASE
is a silicate of copper; other names for it are achirite and Congo
emerald; hardness, 5. The softness and brittleness of this attractive
stone disqualify it for extensive use.
FLUORITE
or fluorspar, of which chloro-phane or cobra stone is a variety, is a
highly lustrous, brittle crystal of wide colour range; hardness, 4.
Varieties of fluorspar are sometimes termed, in the trade, " false"
ruby, emerald, sapphire, and other well-known gem stones.
GOLD-QUARTZ—in
crystals, filiform, reticulated, and arborescent shapes—is commonly
worn as a jewel. Gold penetrating white, black, rose, and amethystine
quartz, is worked into jewelry of all sorts, sometimes of very
elaborate designs. These uses of gold-quartz are most common on the
Pacific coast and in western North American cities.
HEMATITE,
composed of iron 70, oxygen 30, is commonly cut into beads, charms, and
intaglios. Chromic iron and ilmenite are similarly used. Although this
iron ore is steel-grey,
