gemstone

Likely gray moonstone or feldspar cabochon

Most plausibly orthoclase feldspar, KAlSi₃O₈; identification is uncertain from the photo

AI-generated identification · may be incorrect

Small, rounded, opaque-to-translucent gray stone with a smooth, polished surface. If feldspar, hardness is about 6 on the Mohs scale, with vitreous luster and two cleavage directions; crystal structure is monoclinic for orthoclase.

Identified October 15, 2026More gemstone →

Explore Likely gray moonstone or feldspar cabochon in the encyclopedia →

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Physical properties

Formation & geological history

Feldspar forms in cooling igneous rocks and in metamorphic rocks; its age depends on the source deposit. The specimen appears shaped and polished, but the image does not establish its precise mineral identity.

Uses & applications

Feldspar gemstones are used in jewelry and as collectible cabochons; feldspar minerals are also used in ceramics and glassmaking.

Geological facts

Moonstone’s characteristic floating sheen (adularescence) is not clearly visible here, so the name cannot be confirmed from appearance alone.

Field identification & locations

A hardness test, examination of cleavage, and checking for adularescence would help distinguish feldspar from other gray stones. Feldspars occur worldwide in granites and pegmatites.