Moonstone (in a halo ring setting)

Orthoclase Feldspar (containing alternating layers of Albite), (KAlSi3O8)

Rock Type: mineral

Moonstone (in a halo ring setting)

Physical Properties

Hardness: 6.0-6.5 (Mohs scale); Color: Colorless to white with blue/white adularescence; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Specific Gravity: 2.56-2.59

Formation & Geological History

Formed from molten rock or magma. As the magma cools, orthoclase and albite separate into alternating layers. When light falls between these layers, it scatters in many directions, producing the adularescence effect.

Uses & Applications

Primarily used in jewelry (rings, pendants, earrings) and as a birthstone for June. Highly valued by collectors for specimens displaying exceptional schiller effects.

Geological Facts

Ancient Romans believed moonstones were formed from frozen droplets of moonlight. It is the state gem of Florida, chosen to commemorate the Apollo moon landings, even though moonstone is not naturally found on the Moon.

Field Identification & Locations

Identify in the field by its distinct 'billowy' blue or white light (adularescence) that moves across the surface. Key locations include Sri Lanka, Myanmar, India, and Madagascar.

Identified on: 4/19/2026

Mode: Standard