Chalcedony is a cryptocrystalline variety of quartz. It has a fine fiber structure. It has many varieties, the color of which varies greatly: carnelian, carnelian, sard, heliotrope, chrysoprase, sapphirine (not to be confused with the mineral sapphirine). Used in jewelry. Patterned chalcedony is called agate, black-and-white striped chalcedony is called onyx. Pseudo-stalactites of chalcedony are especially valued among collectors. Known since ancient times. Widely used in ancient Rome and Greece.
You can see chalcedony stone for sale and buy it in the Minerals of Russia online store.
|Category||Oxide minerals, quartz group|
|Silica (silicon dioxide, SiO2)|
|Crystal system||Trigonal or monoclinic|
|Formula mass||60 g/mol|
|Fracture||Uneven, splintery, conchoidal|
|Mohs scale hardness||6–7|
|Luster||Waxy, vitreous, dull, greasy, silky|