Quartz · Chalcedony

Black Chalcedony (Onyx)

Black onyx is almost always dyed chalcedony, delivering uniform sleek black for beads, cameos and inlay. Natural black chalcedony is rare, so uniformity itself hints at treatment.

Colour
grey

Transparency
Opaque

RI
1.530–1.539

SG
2.55–2.70

Mohs
6.5–7.0

Birthstone
March · August · May · July

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Black Chalcedony (Onyx)

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