Phenomenal Feldspars. Aventurine. There are three phenomenal feldspars: Sun stone (Aventurine), Moonstone and Labrador Spar or Labradorite. Of these the sunstone owes its peculiar beauty to the presence of spangles of either hematite, gothite or mica. The name has also been applied to a compact quartzite, usually red, brownish or white, with spangles of mica. This aventurine quartzite is found in several parts of Siberia, sometimes in masses weighing more than a ton and is called by the Russians eorletz.D Numerous vases, cups and ornaments are made of this material by the Russians and two great vases formed of it were presented, one to Sir Roderick Murchison and one to Baron Von Humboldt, when they visited Russia in 1850. A greenish or white quartzite, having spangles of mica, or a green ish chlorite, or both, is said to come from India and is occasionally sold as jade.
Californite is a compact variety of vesuvia nite, named by George F. Kunz and is found in Siskiyou County, Cal. A somewhat sim ilar variety was discovered in 1889, on the Piz Longhin, Canton Grisons, Switzerland. When cut en cabochon, its bright green hue acquires great brilliancy and resembles that of the nephrite variety of jade, for which it is occasionally mistaken.
Among the finest gem collections in the United States are the Tiffany-Morgan collec tion and the Bement-Morgan collections at the American Museum of Natural History, New York; the Isaac Lea collection, at the United States National Museum, Washington, D. C. the Tiffany collection of the Field Museum of Natural History, Chicago; the Tiffany collection of the Golden Gate Museum, San Francisco, and the Kunz collection at the New York State Museum, Albany, N. Y. The foreign collections contain many fine gems and are in the collections of the British Museum; the Musee d'Histoire Naturelle, Paris; the Na tional Mineralogical Collection at Vienna, Austria; the Mining Institute, Petrograd, Russia.
Bibliography.— King,
Stones and Metals' ' • Kunz, AGems and Precious Stones of North America' ; Bauer, (Edelsteinkund0 ; Brauns,