Encyclopedia > Chalcedony

  Article Content

Chalcedony

Chalcedony is one of the cryptocrystalline varieties of the mineral quartz, having a waxy lustre. It may be semitransparent or translucent and is usually white to gray or grayish-blue or some shade of brown, sometimes nearly black. Other shades have been given different names. A clear red chalcedony is known as carnelian or sard[?]; a green variety colored by nickel oxide is called chrysoprase[?]. Prase[?] is a dull green. Plasma is a bright to emerald-green chalcedony which is sometimes found with small spots of jasper resembling blood drops; it has been referred to as blood stone[?] or heliotrope[?]. The term chalcedony is derived from the Greek word meaning Chalkedon[?], a town in Asia Minor.

See also: list of minerals



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Museums in England

... Museum[?], Cambridge Cornwall Barbara Hepworth Museum[?], St. Ives, Cornwall Penlee House, Penzance[?] Tate St. Ives[?] Cumbria Abbot ...

 
 
 
This page was created in 54.5 ms