Chalcedony is the cryptocrystalline form of quartz — submicroscopic interlocked quartz fibers producing a tough, waxy-lustered material. Many named varieties are Chalcedony: agate (banded), carnelian (red-orange), chrysoprase (apple-green Ni), bloodstone (green with red jasper), and onyx (parallel-banded). Chalcedony forms in basalt cavities and silica-replacement environments.
Key Facts
- Mohs hardness 7.
- Cryptocrystalline quartz; submicroscopic fibrous texture.
- Waxy luster diagnostic vs. crystalline quartz’s vitreous luster.
- Includes major varieties: agate, carnelian, chrysoprase, bloodstone, onyx, sard.
- Used since prehistoric times for tools, beads, and seal-stones.
Notable Localities
Idar-Oberstein (Germany) historic source; Brazil and Uruguay yield massive material. Marlborough (Australia) supplies chrysoprase.
Found at these Localities
- Eastern Brazilian Pegmatite Province (巴西东部伟晶岩省)
- Oumjrane Mining Area (奥姆贾兰矿区)
- Bou Azzer District (布·阿扎尔钴矿区)
- Imiter Mine (伊米泰尔银矿)
- Rapid Creek (Yukon) (育空地区急流溪磷酸盐产地)
- Tri-State Mining District (Joplin) (三州矿区(乔普林))
- Swiss Alps (Alpine-Cleft Province) (瑞士阿尔卑斯高山裂隙矿物产地)
- Maharashtra Deccan Traprock Zeolites (马哈拉施特拉德干玄武岩沸石产地)
- Trimouns Talc Mine (特里穆滑石矿(法国))
- Siegerland District (西格兰铁矿区)
- Příbram (普日布拉姆银矿)
- Cornwall Mining District (康沃尔矿区)
- Ural Emerald Mines (乌拉尔祖母绿矿)
- Kongsberg (康斯堡银矿)
- Kharan, Balochistan (卡兰板钛矿产地)
- Kalgoorlie–Boulder (卡尔古利金碲矿)
- Săcărâmb (Nagyág) (萨卡拉姆布金碲矿)
- Panasqueira (帕纳斯凯拉钨矿)
- Cavradi Gorge (卡瓦拉迪峡谷)
- Volyn (Volodarsk-Volynskii) (沃伦伟晶岩区)
- Skardu / Shigar Valley (斯卡都/希加尔峡谷)
- Madagascar Pegmatites (Sahatany / Antsirabe) (马达加斯加伟晶岩区)
- Sweet Home Mine (甜蜜之家矿)
- Ouro Preto Region (欧鲁普雷图矿区)
- Llallagua (Siglo XX) (亚亚瓜矿)
- Erongo Mountains (埃龙戈山)
- Heqing Cu-Ag-Pb-Zn District (鹤庆铜银铅锌矿区)
- Yangla Copper Mine (羊拉铜矿)
- Xinglonggou (Fushun Amber Beds) (兴隆沟琥珀产地(抚顺))
- Shimen Realgar-Orpiment Mine (石门雄黄雌黄矿)
- Xiaoqinling Gold Field (小秦岭金矿田)
- Ying Silver Mine (银矿(豫西银多金属矿带))
- Erbutu Molybdenum Mine (二八图钼矿)
- Dachang Tin-Polymetallic Field (大厂锡多金属矿田)
- Yaogangxian Mine (瑶岗仙矿)
- Hubei (湖北)
- Sichuan (四川)
- Hunan (湖南)
Available Products of Chalcedony
4 available specimens
Varieties of Chalcedony
Chalcedony is a parent species — the following named varieties differ in color or chemistry but share the same fundamental mineralogy.
- Onyx (u7f1fu739bu7459)parallel banded black-and-whiteBlack-and-white parallel-banded chalcedony variety, used for cameos.
- Sardonyx (u7ea2u7f1fu739bu7459)red-and-white bandedRed-and-white parallel-banded chalcedony, used for cameos and intaglios.
- Carnelian (u7ea2u7389u9ad3)red-orangeIron-bearing reddish-orange chalcedony variety.
- Sard (u6df1u8910u7389u9ad3)brownish-redDarker-brown carnelian-related chalcedony variety.
- Chrysoprase (u7effu7389u9ad3)apple-greenNickel-bearing apple-green chalcedony variety; the rarest chalcedony color.
- Bloodstone (Heliotrope) (u8840u77f3)green with red spotsDark-green chalcedony with red iron-oxide spots resembling blood drops.
