gemstone

Black faceted gemstone, possibly black spinel or onyx

Undetermined; candidates include spinel (MgAl₂O₄) or chalcedony (SiO₂)

AI-generated identification · may be incorrect

Small, opaque-to-translucent black faceted piece with a vitreous-looking surface. Hardness and crystal structure cannot be established from the image; the dark appearance could also come from coating or glass imitation.

Identified October 3, 2026More gemstone →

Explore Black faceted gemstone, possibly black spinel or onyx in the encyclopedia →

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Physical properties

Formation & geological history

The image does not allow reliable identification or dating. Spinel forms in metamorphic and igneous settings; chalcedony forms as microcrystalline silica in cavities and fractures.

Uses & applications

Likely intended for jewelry or craft use; value depends on material, size, cut, and whether it is natural or synthetic.

Geological facts

Black spinel and black chalcedony are both used as dark jewelry stones, but appearance alone cannot distinguish them from glass or coated simulants.

Field identification & locations

A gemological test is needed: inspect under magnification and test refractive index or hardness; avoid scratch testing a finished piece. The photo provides no reliable locality information.