Leucostaurite is an exceptionally rare lead borate mineral primarily found in the Friedrichssegen mine near Bad Ems, Germany. It typically forms small, white to colorless tabular crystals that can be difficult to distinguish from other colorless secondary minerals without advanced testing.
Is this leucostaurite?
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 leucostaurite with a known reference. Leucostaurite sits at Mohs ~4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Leucostaurite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Leucostaurite is noticeably harder (Mohs ~4 vs. 2-2.5); luster reads adamantine on Leucostaurite and vitreous to resinous, may be earthy on Borax.
How to tell apart: Luster reads adamantine on Leucostaurite and vitreous to adamantine on Colemanite.
Often found alongside leucostaurite
Minerals reported to co-occur with leucostaurite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂B₅O₉Cl(H₂O)₀.₅
- Mohs hardness
- ~4
- Density
- 5.071 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular crystals
- Cleavage
- Perfect on {010}, good on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral by the interaction of evaporitic brines within the oxidation zone of a base-metal deposit
Where rockhounds find leucostaurite
Classic worldwide localities
- Asunción mine, Sierra Gorda, Atacama Desert, Caracoles District, Antofagasta Province, Chile
Field-hunting tip
Where it forms: A secondary mineral by the interaction of evaporitic brines within the oxidation zone of a base-metal deposit. If you start seeing boleite, paralaurionite, caracolite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify leucostaurite?+
Where is leucostaurite found?+
Is leucostaurite safe to handle?+
What rocks look like leucostaurite?+
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Find leucostaurite on the map
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