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Chalcedony — specimen 0183, photo © NMNHS
Chalcedony — specimen 0183, photo © NMNHS

Chalcedony — specimen 0183

Origin

no precise locality [Africa]
Data

Weight: 1.06 ct; size: 7.11 | 5.08 | 3.85 mm; shape: oval; colour: medium dark bluish purple; strong; clarity: translucent; cut: fair; treatment: none.
Notes

Clean specimen; cabochon style cut.

Other specimens
Chalcedony — specimen 0088Chalcedony — specimen 0403Chalcedony — specimen 0180Chalcedony — specimen 0510Chalcedony — specimen 0511Chalcedony — specimen 0512Chalcedony — specimen 0580Chalcedony — specimen 0591Chalcedony — specimen 0225Chalcedony — specimen 0688Chalcedony — specimen 0418Chalcedony — specimen 0558Chalcedony — specimen 0179Chalcedony — specimen 0404Chalcedony — specimen 0265Chalcedony — specimen 0348Chalcedony — specimen 0684Chalcedony — specimen 0685

More specimens

More information from ‘Classification’

Chalcedony

Traditionally defined as a fibrous cryptocrystalline variety of quartz. More recently, it has been shown that much chalcedony is a mixture of quartz and mogánite. Pure chalcedony may contain trace amounts of silanol groups.


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The specimens illustrated in this site do not exist in the collections of the National Museum of Natural History, Sofia.