Moonstone
Orthoclase Feldspar (KAlSi3O8)
Rock Type: mineral

Physical Properties
Hardness: 6-6.5 Mohs scale, Color: Transparent to translucent white/blue, Luster: Vitreous to pearly, Crystal structure: Monoclinic, Cleavage: Perfect in two directions, Specific gravity: 2.56-2.59
Formation & Geological History
Formed in high-temperature igneous and metamorphic environments, specifically pegmatites. The visual effect (adularescence) is caused by the intergrowth of two types of feldspar that separate as the mineral cools.
Uses & Applications
Primarily used in jewelry (cabochons, rings, pendants) and popular among crystal collectors for its aesthetic and perceived metaphysical properties.
Geological Facts
Moonstone is the state gem of Florida to commemorate the moon landings, despite not being found naturally there. The high-quality blue sheen specimens are highly sought after.
Field Identification & Locations
Identify in the field by its distinct adularescence (a milky sheen or glow that moves across the surface). Most commonly found in Sri Lanka, India, Myanmar, and Madagascar.
Identified on: 4/19/2026
Mode: Standard