Chalcedony

Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of the minerals quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic. Chalcedony's standard chemical structure (based on the chemical structure of quartz) is SiO2 (silicon dioxide).
Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black.
Chalcedony occurs in a wide range of varieties. Many semi-precious gemstones are in fact forms of chalcedony. The more notable varieties of chalcedony are as follows: Agate, Aventurine, Carnelian, Chrysoprase, Heliotrope, Moss Agate, Mtorolite, Onyx,  

All the Chalcedony minerals we offer are from Mali in western Africa.

 

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Chalcedony-01- Nioro Area Mali
Sky Blue Chalcedony on matrix in excellent condition.  From Diaye Coura, Nioro are..
$0.00 USD
Ex Tax: $0.00 USD
Chalcedony-02- Nioro Area Mali
Sky-blue Chalcedony mineral, part of a geode, no damage. From Diaye Coura, Nioro area, Kayes..
$0.00 USD
Ex Tax: $0.00 USD
Chalcedony-03- Nioro Area Mali
Sky-blue Chalcedony mineral, part of a geode, no damage. From Diaye Coura, Nioro area, Kayes..
$50.00 USD
Ex Tax: $50.00 USD
Chalcedony-04- Nioro Area Mali
Blue Chalcedony, from Diaye Coura, Nioro area, Kayes Region, Mali. 10.5 x 8.5 x 5.2 cm (Larg..
$0.00 USD
Ex Tax: $0.00 USD
Chalcedony-05- Rio Grande Do Sul Brazil
Blue to Grey and white Chalcedony with little terminated Quartz displaying some nice patterns f..
$0.00 USD
Ex Tax: $0.00 USD