A transparent, or more generally, a translucent cryptocrystalline quartz; the material of agate
A cryptocrystalline, translucent variety of quartz, having usually a whitish color, and a luster nearly like wax
[kalcedony] A precious stone, consisting of half - transparent quartz: so called from Chalcedon, in Asia Minor, where it was first found Its chief varieties are agate, carnelian, cat's-eye, chrysoprase, flint, hornstone, onyx, plasma, and sard Albertus Magnus (book i chap 2) says: It dispels illusions and all vain imaginations If hung about the neck as a charm, it is a defence against enemies, and keeps the body healthful and vigorous
A semi-translucent silicate (quartz) rock with a wax-like luster and a great range of colours, used as raw material for the manufacture of chipped stone artifacts Commonly called agate
A form of fine-grained quartz that is transparent or has a milky translucence and exhibits a conchoidal fracture
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
A type of microcrystalline quartz with hydrated silica (opal) It appears naturally in bluish greys to brownish-reddish colors to white or cream Because of its molecular structure, it is very porous and easy to dye The name is derived from an ancient town along the Bosphorus A R T Precious & Collectible Jewelry