Moonstone (specifically Rainbow Moonstone / White Labradorite)

Physical Properties

Hardness: 6–6.5 (Mohs scale); Color: White with grey/black inclusions (biotite/tourmaline) and blue 'adularescence' flashes; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Two directions at nearly 90 degrees; Specific gravity: 2.6 – 2.7.

Formation & Geological History

Formed in igneous environments (plutonic rocks like pegmatites) and metamorphic rocks. The characteristic 'glow' results from the intergrowth of two types of feldspar that separate as the mineral cools.

Uses & Applications

Predominantly used as a gemstone in jewelry (rings, pendants, earrings), and as a metaphysical or collector's specimen.

Geological Facts

Despite the name, 'Rainbow Moonstone' is technically a variety of Labradorite rather than True Moonstone (Orthoclase). Legend has it that moonstones are made of solidified moonbeams.

Field Identification & Locations

Identify in the field by its pearly luster, typical feldspar cleavage planes, and the 'shiller' or blue flash effect when rotated under light. Often found in India, Sri Lanka, Madagascar, and Canada.

Identified on: 4/18/2026

Mode: Standard