Quartz is prized by both mineral collectors and lapidary artists.Over 130 vivid photographs of these beautiful minerals are presented to show each mineral in its geological context.Superb examples are found in diverse geological settings from pegmatites to Alpine clefts and hydrothermal veins.The silica minerals are chemically simple, yet structurally complicated.Several high temperature and high pressure polymorphs are known.In addition to the polymorphs of silica, this book treats related minerals, including: lechatelierite, opal, and two natural clathrates, chibaite and melanophlogite.After a brief introduction, the general treatment explains the chemistry and taxonomy of the group.A section on their formation and geochemistry describes the kinds of environments where these minerals are formed.Then, entries for each mineral provide locality information and full-color photos so that collectors can see what good specimens look like and which minerals one might expect to find in association with them.An extensive bibliography is also provided.