Gemstone profile and identification guide

Rainbow Moonstone

Rainbow moonstone is a trade name typically applied to white labradorite showing colorful flash.

6 Mohs White, Blue Flash Silicate (Feldspar Trade Name, typically Labradorite Variety)

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Overview

Rainbow moonstone is a trade name typically applied to white labradorite showing colorful flash.

Did you know? Strong blue flash in rainbow moonstone often indicates plagioclase feldspar structure.

Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.

Identification

Name: Rainbow Moonstone

Scientific classification: Silicate (Feldspar Trade Name, typically Labradorite Variety)

Hardness: 6 Mohs

Transparency: translucent

Lustre: vitreous

Crystal system: Triclinic

Primary colour: White

Secondary colour: Blue Flash

Colour family: Whites & Neutrals

Trade name does not equal orthoclase species; gemological testing may confirm feldspar subtype.

Verification Status

Status: verified-core-fields

Reference priority: GIA, Gem-A, Mindat, International Gem Society

Core identity, locality, and physical-property fields reviewed against standard gemological references.

Trade-name and treatment-sensitive entries include explicit disclosure notes where applicable.

Physical Properties

Hardness category: hard

Hardness value: 6 Mohs

Chemical composition: Sodium-calcium feldspar series, commonly labradorite composition

Crystal system: Triclinic

Common locations: India, Sri Lanka, Madagascar

Learn more: Gem-A gemstone education resources.

Colour Variations

Light feldspar body color with vivid blue or multicolor adularescent/labradorescent flashes.

Optical effects: Adularescence, Labradorescence

Detailed Gemology

Mineral species: Typically labradorite feldspar (trade as rainbow moonstone)

Mineral group: Feldspar group

Chemical formula: Sodium-calcium feldspar series, commonly labradorite composition

Mohs hardness: 6

Crystal system: Triclinic

Lustre: vitreous

Transparency: translucent

Streak: White

Cleavage: Perfect in two directions

Fracture: Uneven

Specific gravity: 2.68-2.74

Refractive index: 1.54-1.56

Optical phenomena: Blue flash and multicolor interference effects

Colour range: White to colorless body with blue/rainbow flashes

Common inclusions: Lamination, cleavage traces, fissures

Geological environment: Igneous feldspar-bearing rocks and pegmatitic systems

Principal mining regions: India, Sri Lanka, Madagascar

Important commercial sources: Rainbow moonstone in trade is usually white labradorite rather than orthoclase moonstone

Historical significance: Widely marketed modern feldspar jewelry trade stone.

Common treatments: Generally untreated.

Synthetic or imitation forms: Coated glass and synthetic substitutes can imitate flash.

Common look-alikes: Opalite glass, white labradorite variants, moonstone simulants

Jewellery uses: Used in cabochons, faceted accent stones, and designer jewellery.

Care recommendations: Rainbow Moonstone should be cleaned with lukewarm water, mild soap, and a soft brush. At Mohs 6 in the Triclinic system, avoid steam cleaners, harsh chemicals, and high-impact wear. Protect cleavage directions from sharp knocks during wear and setting.

Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Rainbow Moonstone.

Formation

Feldspar exsolution structures create optical interference effects.

Origin

Rainbow moonstone in trade is usually white labradorite rather than orthoclase moonstone

Uses

Best for: Used in cabochons, faceted accent stones, and designer jewellery.

Ideal uses: Cabochons showcasing strong blue flash.

Care

Rainbow Moonstone should be cleaned with lukewarm water, mild soap, and a soft brush. At Mohs 6 in the Triclinic system, avoid steam cleaners, harsh chemicals, and high-impact wear. Protect cleavage directions from sharp knocks during wear and setting.

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