mineral

Moonstone

Orthoclase (KAlSi3O8) with Albite (NaAlSi3O8)

Hardness: 6.0-6.5 (Mohs scale), Color: Colorless to white/cream with blue or white adularescence (schiller), Luster: Vitreous to pearly, Crystal structure: Monoclinic, Cleavage: Two directions at 90 degrees, Specific gravity: 2.56-2.59

Hardness: 6

Identified July 13, 2026More mineral →

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Physical properties

Formation & geological history

Moonstone is a variety of the feldspar group. It forms through the intergrowth of two types of feldspar, orthoclase and albite, which separate into layers as the magma cools. The adularescence occurs when light enters the many thin layers of the stone and scatters.

Uses & applications

Primarily used as a gemstone in jewelry such as rings, pendants, and earrings. It is also a popular specimen for crystal collectors.

Geological facts

Ancient Romans and Greeks theorized that moonstones were born from solidified rays of the moon. It was highly popular during the Art Nouveau era and is the state gem of Florida to commemorate the moon landing.

Field identification & locations

Field identification focuses on the internal blue or white glow (adularescence) that moves across the stone as it is turned. Common locations include Sri Lanka, India, Myanmar, Australia, and Brazil. Collectors should look for high clarity and strong color play.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock