Encyclopedia

chalcedony

chalcedony (kălsed'unē) [key][from Chalcedon], form of quartz the crystals of which are so minute that its crystalline structure cannot be seen except with the aid of a microscope. Chalcedony has a waxy luster and is translucent to transparent. The name chalcedony is applied more specifically to white, gray, blue, and brown varieties. Some varieties, differing in color because of the presence of impurities, are agate, bloodstone, carnelian, chrysoprase, jasper, onyx, sard, and sardonyx.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2007, Columbia University Press. All rights reserved.

More on chalcedony from Fact Monster:

  • Chalcedony - Chalcedony [kalcedony]. A precious stone, consisting of half-transparent quartz: so called from ...
  • bloodstone - bloodstone bloodstone or heliotrope,green chalcedony spotted with red, used as a gem stone. It is ...
  • carnelian - carnelian carnelian or cornelian, variety of red chalcedony, used as a gem. It is distinguished ...
  • geode - geode geode , hollow, globular rock nodule ranging in diameter from 1 to 12 in. (2.54–30.5 ...
  • quartz - quartz quartz, one of the commonest of all rock-forming minerals and one of the most important ...

See more Encyclopedia articles on: Mineralogy and Crystallography
© 2000–2008 Pearson Education, publishing as Fact Monster