Hobbies And Interests
Agates and Jasper
Agate and jasper come in a rainbow of colors. Though they're varieties of quartz, they contain tiny fibers and grains that can only be seen through a microscope. Chalcedony includes all agates and is made of ultra thin layers of quartz fibers. This can be seen in the color banding in agate. Because of this layering, chalcedony is very tough and is a good carving material. Pure chalcedony is translucent gray or white; its color comes from impurities. Iron oxide creates the brown coloring in agates and sardonyx. Jasper is a mass of tiny interlocking quartz crystals. It's opaque and has impurities that give it color. Jasper is used for carvings and in mosaics.
Citrine and Amethyst
The purple of amethyst and the yellow of citrine are also caused by impurities -- in their case, iron. According to myth, amethyst, with its seductive color, is thought to protect its wearer against seduction. It's also supposed to offer protection against drunkenness, for its name means "not intoxicated." Amethyst is also supposed to protect against storms and locusts, bring good fortune in war and the hunt and cast out evil spirits. Some amethysts lose their color in daylight, but can be recolored through radium radiation. Naturally yellow citrine is hard to find and most yellow citrine is commercially manufactured. Very fine and transparent amethyst and citrine are faceted; others are made into cabochons.
Rose Quartz, Tiger's Eye, Smoky Quartz
The colors of rose quartz come from titanium and iron, and sometimes there are needles of rutile in the powder-pink gem, which causes a star effect. Tiger's eye is formed when asbestos is replaced by quartz. The asbestos leaves either brown iron oxides in tiger's eye or the original blue color, as in hawk's eye. Smoky quartz is a brown transparent quartz used for unusual faceted cuts.
Onyx
Onyx is a black chalcedony quartz and sometimes shows white bands or ribbons when put against a black backdrop. It's sometimes carved into cameos and was very popular with the ancient Greeks and Romans. The name comes from the Greek word for claw, because Eros is supposed to have cut the fingernails of Aphrodite while she was sleeping and left the clippings scattered on the sand, where the Fates turned them into stone. Onyx that is reddish brown and white is called sardonyx.