gems, feldspar, moonstone, albite, peristerite, rainbow moonstone, India, locality, species

This note examines colourless to milky-white, transparent to semitransparent feldspar from India marketed as “rainbow moonstone.” The material displays both adularescence and labradorescence, with physical properties corresponding to andesine. Microscopic examination reveals features characteristic of labradorescent plagioclase, particularly polysynthetic twinning lamellae and cleavage fractures. These observations clarify the mineralogical identity of material sold under this trade name.