Quick Facts
Formation & Origin
Here's a fact that surprises many crystal enthusiasts: rainbow moonstone is not actually moonstone. Mineralogically, it's a transparent to translucent variety of labradorite (a plagioclase feldspar) with a white body and blue-to-multicolor flash (labradorescence). True moonstone is orthoclase (a potassium feldspar) with adularescence, a billowy, moving glow.
The 'rainbow' effect in rainbow moonstone comes from the same mechanism as in standard labradorite: light diffracting off submicroscopic layers of alternating feldspar compositions within the crystal. In labradorite, these layers create the famous play of color. In rainbow moonstone, the host crystal is transparent enough to show this effect against a white or clear background.
The trade name 'rainbow moonstone' persists because it sells better than 'white labradorite' and because the visual effect (a luminous glow from within a translucent white stone) does resemble moonstone to the casual observer. Both the FTC and gemological labs recognize the name as a trade convention while noting the mineralogical distinction.
Identification Guide
Rainbow moonstone shows blue to multicolor flashes (labradorescence) in a white translucent body. True moonstone shows a softer, billowy adularescence (typically blue or white) without the sharp, colorful flashes.
Distinguish from true moonstone (adularescence vs. labradorescence), opalite (man-made glass, too uniform), and white labradorite (same mineral, different trade name). The sharp, colorful flashes visible when tilted distinguish rainbow moonstone from the softer glow of true moonstone.
Spotting Fakes
Opalite (man-made opalescent glass) is widely sold as rainbow moonstone. Opalite has a uniform, milky blue glow that doesn't change dramatically with angle, while genuine rainbow moonstone shows distinct flashes that appear and disappear as you tilt the stone. Under magnification, rainbow moonstone shows natural inclusions and internal layering, while opalite is perfectly clean. Weight is another clue: feldspar is denser than glass.
Cultural & Metaphysical Traditions
Presented as cultural traditions, not scientific evidence
Rainbow moonstone carries the metaphysical associations of both moonstone and labradorite. It's considered a stone of new beginnings, feminine energy, and intuition (from the moonstone tradition) combined with transformation and psychic protection (from the labradorite tradition). Practitioners value it for connecting to lunar cycles and enhancing dream awareness.
Where It's Found
Primary commercial source
Fine quality material
Growing source
Some fine specimens
Price Guide
Good to Know
Scratch test: At hardness 6, Rainbow Moonstone resists scratching from a knife but can be scratched by quartz. Best for pendants and earrings rather than rings.
Sources: Found in 4 notable locations worldwide, from India to Myanmar.
Heft test: Rainbow Moonstone has average mineral density (2.69-2.72). It feels about as heavy as you'd expect from a stone its size.