Rainbow Moonstone with Black Tourmaline

Physical Properties

Mohs Hardness: 6-6.5. Color: White to translucent with blue schiller (adularescence) and black inclusions. Luster: Vitreous to pearly. Crystal structure: Triclinic. Specific gravity: 2.56-2.59.

Formation & Geological History

Formed in plutonic igneous rocks and metamorphic rocks through high-temperature mixtures of feldspar that separate as they cool. The blue flash is caused by light interference between layers of different feldspar minerals.

Uses & Applications

Extensively used in jewelry (cabochons, beads) and as a decorative or metaphysical stone for collectors.

Geological Facts

While commonly called "Rainbow Moonstone," it is technically a variety of Labradorite feldspar rather than a true Orthoclase moonstone. The black inclusions are typically Schorl, the most common variety of Tourmaline.

Field Identification & Locations

Identified by its characteristic labradorescence (blue flash) across a white base. Often found in India, Madagascar, and Sri Lanka. For collectors, the value increases with the intensity and coverage of the blue flash.

Identified on: 4/29/2026

Mode: Standard