Trébeurdenite is a rare member of the hydrotalcite group characterized by its platy, pseudo-hexagonal crystal habit and distinct green color. It is typically found as a secondary mineral in altered metamorphic environments, often requiring microscopic study for positive identification.
Is this trébeurdenite?
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 trébeurdenite with a known reference. Trébeurdenite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Trébeurdenite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Trébeurdenite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: green, yellowish-green, pale green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, pseudo-hexagonal.
Often confused with
Trébeurdenite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside trébeurdenite
Minerals reported to co-occur with trébeurdenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₂Mg₆(OH)₁₆CO₃·4H₂O
- Mohs hardness
- 2
- Density
- 2.16 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals, Pseudo-hexagonal
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Metamorphic Rocks
- Typical price
- $20-100 per specimen
Where rockhounds find trébeurdenite
Classic worldwide localities
- Trébeurden, Brittany, France
- various hydrothermal occurrences
Field-hunting tip
Look in hydrothermal veins in metamorphic rocks country, the host setting where trébeurdenite typically forms. If you start seeing goethite, magnesite, serpentine in float, you are in the right ground. Field specimens usually show a platy crystals, pseudo-hexagonal habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify trébeurdenite?+
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What rocks look like trébeurdenite?+
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Find trébeurdenite on the map
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