White Corundum, also known as Leucosapphire, is the colorless variety of the mineral species corundum. It is characterized by its extreme hardness and high density, often found as hexagonal barrel-shaped crystals in metamorphic marble deposits or alluvial gravels.
Is this white corundum?
5-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 corundum with a known reference. White Corundum sits at Mohs 9 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. White Corundum leaves a none streak.
- 3Read the lusterHold the specimen under a strong light. White Corundum typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: hexagonal prisms and tabular crystals.
Often confused with
White Corundum vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: White Corundum is noticeably harder (Mohs 9 vs. 8); streak differs — White Corundum leaves none, Topaz leaves white.
How to tell apart: White Corundum is noticeably harder (Mohs 9 vs. 7); streak differs — White Corundum leaves none, Quartz leaves white.
How to tell apart: White Corundum is noticeably harder (Mohs 9 vs. 7.5); streak differs — White Corundum leaves none, Zircon leaves white; luster reads vitreous on White Corundum and adamantine on Zircon.
Often found alongside white corundum
Minerals reported to co-occur with white 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
- 4.02 g/cm³
- Streak
- None
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Hexagonal Prisms and Tabular Crystals
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Abrasive, Gemstone
- Host rock
- Metamorphic Rocks Like Marble and Gneiss, Or Igneous Pegmatites
- Typical price
- $20-200 per gram depending on clarity and quality
Where rockhounds find white corundum
1 mapped spotsClassic worldwide localities
- Sri Lanka
- Myanmar
- Madagascar
- Tanzania
- USA
Field-hunting tip
Look in metamorphic rocks like marble and gneiss, or igneous pegmatites country — that is the host setting where white corundum typically forms. If you start seeing spinel, garnet, feldspar in float, you are in the right ground. Field specimens usually show a hexagonal prisms and tabular crystals habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in New York — start trip planning there.
Common questions
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Find white corundum on the map
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