Rainbow Moonstone is technically a variety of Labradorite feldspar that exhibits a characteristic adularescence, or schiller, displaying flashes of blue and multi-colored light. It is commonly found in India and Sri Lanka, often fashioned into cabochons to best display its optical play-of-color. Collectors should look for high translucency and strong blue spectral flashes when evaluating specimens.

Hardness

6-6.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

gemstonecommonOrthoclase family

Rainbow Moonstone

Also: White Labradorite

Hardness: 6-6.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this rainbow moonstone?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch rainbow moonstone with a known reference. Rainbow Moonstone sits at Mohs 6-6.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: white, colorless, blue, rainbow.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals.

Often confused with

Rainbow Moonstone vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Luster reads vitreous on Rainbow Moonstone and waxy on Chalcedony.

Often found alongside rainbow moonstone

Minerals reported to co-occur with rainbow moonstone. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: KAlSi₃O₈
Mohs hardness: 6-6.5
Density: 2.56-2.63 g/cm³
Colors: White Colorless BlueRainbow
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular crystals
Cleavage: Perfect in two directions
Rarity: Common
Uses: Gemstone, Lapidary, Collector
Host rock: pegmatites

Where rockhounds find rainbow moonstone

Classic worldwide localities

India
Sri Lanka
Madagascar
Australia

Field-hunting tip

Where it forms: pegmatites. If you start seeing quartz, muscovite, biotite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

More rainbow moonstone photos

Common questions

How do you identify rainbow moonstone?+

Mohs hardness is 6-6.5. Luster: vitreous. The streak is white. Common colors include white, colorless, blue, rainbow.

Where is rainbow moonstone found?+

Notable localities include India; Sri Lanka; Madagascar; Australia.

What rocks look like rainbow moonstone?+

Rainbow Moonstone is most often confused with Opal, Chalcedony, Albite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with rainbow moonstone?+

Rainbow Moonstone commonly co-occurs with Quartz, Muscovite, Biotite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does rainbow moonstone form in?+

Where it forms: pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is rainbow moonstone used for?+

Rainbow Moonstone is used in gemstone, lapidary, collector.

Find rainbow moonstone on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.