topaz

noun

1. a mineral, a fluosilicate of aluminum, usually occurring in prismatic orthorhombic crystals of various colors, and used as a gem.
2. citrine(def 2).
3. either of two South American hummingbirds, Topaza pella or T. pyra, having chiefly red and crimson plumage and a yellowish-green throat with a topaz sheen.

noun

1. a white or colourless mineral often tinted by impurities, found in cavities in igneous rocks and in quartz veins. It is used as a gemstone. Composition: hydrated aluminium silicate. Formula: Al 2 SiO 4 (F,OH) 2 . Crystal structure: orthorhombic
2. oriental topaz a yellowish-brown variety of sapphire
3. false topaz another name for citrine
4. 1. a yellowish-brown colour, as in some varieties of topaz
   2. (as adjective)topaz eyes
5. either of two South American hummingbirds, Topaza pyra and T. pella

n.

colored crystalline gem, late 13c., from Old French topace (11c.), from Latin topazus, from Greek topazos, topazion, of obscure origin. Pliny says it was named for a remote island in the Red or Arabian Sea, where it was mined, but this might be folk etymology from Greek topazein “to divine, to try to locate;” linguists conjecture a connection with Sanskrit tapas “heat, fire.” In the Middle Ages used for almost any yellow stone. To the Greeks and Romans, possibly yellow olivine or yellow sapphire. In modern science, fluo-silicate of aluminum.

1. A colorless, blue, yellow, brown, or pink orthorhombic mineral valued as a gem. Topaz occurs as transparent or translucent prisms in silica-rich igneous rocks, such as pegmatite, and in tin-bearing rock veins. Chemical formula: Al2SiO4(F,OH)2.
2. Any of various yellow gemstones, especially a yellow variety of sapphire or corundum.