chalcedony (kălsĕd`ənē) [from Chalcedon Chalcedon (kăl`sĭdŏn, –dən, kălsē`dən), ancient Greek city of Asia Minor, on the Bosporus.
..... Click the link for more information. ], 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 agate (ăg`ĭt), translucent, cryptocrystalline variety of quartz and a subvariety of chalcedony .
..... Click the link for more information. , bloodstone, carnelian carnelian (kärnēl`yən) or cornelian
..... Click the link for more information. , chrysoprase, jasper jasper, opaque, impure cryptocrystalline quartz , usually red, but also yellow, green, and grayish blue. It is used as a gem. Ribbon jasper has the colors in stripes.
..... Click the link for more information. , onyx onyx (ŏn`ĭks), variety of cryptocrystalline quartz , differing from agate only in that the bands of which it is composed are
..... Click the link for more information. , sard, and sardonyx.

chalcedony

or calcedony

Very fine-grained variety of the silica mineral quartz. A form of chert, it occurs in a great variety of colours, usually bluish white, gray, yellow, or brown. Other physical properties are those of quartz. For centuries, chalcedony has been the stone most used by gem engravers, and many varieties are still cut and polished as ornamental stones. See also agate; carnelian; onyx.

chalcedony (redirected from calcedony)

chalcedony

chalcedony
(redirected from calcedony)