Chalcedony Variety of Quartz
1. About the Mineral Chalcedony
2. Different Types of Chalcedony
3. More Chalcedony Facts
4. Our Collection of Chalcedony
5. More Information
About the Mineral Chalcedony
The stone chalcedony which it's generally agreed should be pronounced kal~SED~uh~nee is a fine grained or cryptocrystalline variety of quartz. Microcrystalline and cryptocrystalline are both words which tend to be used interchangeably to describe minerals whose crystals are too small to be seen with the naked eye. When the mineral quartz is either microcrystalline or cryptocrystalline it's correctly known as chalcedony.
The mineral chalcedony tends to have a waxy lustre, is usually translucent and can be found in white, grey, blue or brown. The stone can also exhibit many other colours due to the presence of different minerals but inclusions are often microscopic. Blue chalcedony is particularly popular as a lapidary material but stones are frequently dyed.
Graded 6½ to 7 on Mohs scale of mineral hardness means chalcedony is a relatively hard stone and it can be found pretty much worldwide. The finest grade material comes mostly from India, Madagascar, Burma, Brazil, Mexico and the USA.
Different Types of Chalcedony
Jasper, agate, carnelian, onyx, chrysoprase and bloodstone are all varieties of the mineral chalcedony. The colour of carnelian is caused by the presence of iron oxides which are chemical compounds made up of iron and oxygen. The green in chrysoprase is caused by nickel oxide whilst the inclusions in bloodstone are believed to be hematite. Some of the lesser known varieties of chalcedony include plasma, sard and sardonyx. Sard occurs in shades of light to dark brown and sardonyx features bands of sard in addition to white chalcedony. Stones that feature distinctive and colourful bands are mostly referred to as agate but when the bands are black, white or dark brown the stone is correctly known as onyx.
More Chalcedony Facts
The mineral chalcedony has been used by man for thousands of years and is thought to have been one of the earliest materials used for tools and weapons. Other varieties including agate, flint, jasper and petrified wood were also widely used.
Considered to be a sacred stone by the Native American Indians, chalcedony was used to promote stability within their tribes. In ancient times it was used to make goblets lined with silver which were used in the belief they would offer protection against poisoning. Today when chalcedony is used for its healing properties it's said to encourage generosity, protect against nightmares, fear of the dark, hysteria, depression and combat negative thoughts.
Our Collection of Chalcedony