White Star Corundum, also known as colorless sapphire or leucosapphire, is a pure variety of corundum lacking the trace elements required to produce color. It is highly prized by collectors and jewelers for its exceptional hardness and brilliance, often used as a durable diamond alternative.
Is this white star corundum?
4-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch white star corundum with a known reference. White Star Corundum sits at Mohs 9, softer than the next harder reference, harder than the previous one.
- 2Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 3Match the color rangeCompare against the expected color range: white, colorless.
- 4Look at form & habitCrystal system: trigonal. Typical habit: hexagonal prisms or bipyramids.
Often confused with
White Star Corundum vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: White Star Corundum is noticeably harder (Mohs 9 vs. 7).
How to tell apart: White Star Corundum is noticeably harder (Mohs 9 vs. 8).
How to tell apart: White Star Corundum is noticeably harder (Mohs 9 vs. 7.5-8).
Often found alongside white star corundum
Minerals reported to co-occur with white star corundum. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₂O₃
- Mohs hardness
- 9
- Density
- 4.0-4.1 g/cm³
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Hexagonal prisms or bipyramids
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Gemstone, Collector, Jewelry
- Host rock
- metamorphic rocks like marble or gneiss
Where rockhounds find white star corundum
1 mapped spotsClassic worldwide localities
- Sri Lanka
- Madagascar
- Tanzania
- Myanmar
Field-hunting tip
Where it forms: metamorphic rocks like marble or gneiss. If you start seeing spinel, garnet, zircon in float, you are in the right ground. Typical habit: hexagonal prisms or bipyramids. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in North Carolina. Start trip planning there.
Common questions
How do you identify white star corundum?+
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What rocks look like white star corundum?+
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Find white star corundum on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
