Laachite is a calcium manganese zirconium oxide, typically deep brownish red. It occurs in vesicular sanidinite volcanic ejectum. It was first described from the "Zieglowski" pumice quarry, Eifel volcanic region, Rheinland-Pfalz, Germany.
Is this laachite?
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 laachite with a known reference. Laachite sits at Mohs 7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish red.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: deep brownish red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive.
Often confused with
Laachite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Laachite leaves brownish red, Quartz leaves white; luster reads adamantine on Laachite and vitreous; waxy to dull when massive on Quartz.
How to tell apart: Streak differs, so Laachite leaves brownish red, Chalcedony leaves white; luster reads adamantine on Laachite and waxy on Chalcedony.
Often found alongside laachite
Minerals reported to co-occur with laachite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Mn)₂Zr₂Nb₂TiFeO₁₄
- Mohs hardness
- 7
- Density
- 5.417 g/cm³
- Colors
- Deep brownish red
- Streak
- Brownish red
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector
- Host rock
- In vesicular sanidinite volcanic ejectum
Where rockhounds find laachite
Classic worldwide localities
- "Zieglowski" pumice quarry, Rheinland-Pfalz, Germany
Field-hunting tip
Where it forms: In vesicular sanidinite volcanic ejectum. If you start seeing sanidine, allanite-, baddeleyite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify laachite?+
Where is laachite found?+
What rocks look like laachite?+
What minerals are found with laachite?+
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Find laachite on the map
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