mineral

Moonstone (Tumbled)

Potassium Aluminum Silicate (KAlSi3O8) with inclusions of Albite

Hardness: 6-6.5 (Mohs scale), Color: Creamy white to pale tan, Luster: Vitreous to pearly, Crystal Structure: Monoclinic, Cleavage: Perfect in two directions. Shows adularescence (a blue or white sheen) when light hits it at certain angles.

Hardness: 6-6

Identified June 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous and metamorphic rocks, particularly pegmatites. The characteristic sheen is caused by the intergrowth of two types of feldspar (orthoclase and albite) that separate as the mineral cools.

Uses & applications

Primary use is in jewelry as a gemstone, especially in rings, pendants, and earrings. It is also a very popular specimen for crystal healing and mineral collecting.

Geological facts

The ancient Romans theorized that moonstone was formed from frozen beams of moonlight. It is the state gem of Florida to commemorate the moon landing.

Field identification & locations

Identify in the field by its distinct pearly luster and internal shimmers. It is commonly found in Sri Lanka, India, Myanmar, and Madagascar. Tumbled stones like this are often smoothed in a rock tumbler over several weeks.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock