Lavoisierite is a rare manganese silicate mineral typically found as small, prismatic crystals in high-grade metamorphic deposits. It is structurally related to gaudefroyite and is highly prized by collectors for its limited locality and unique chemical composition.
Is this lavoisierite?
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 lavoisierite with a known reference. Lavoisierite sits at Mohs 6-7, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: yellow-orange.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals.
Often confused with
Lavoisierite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Lavoisierite leaves white, Gaudefroyite leaves brown.
How to tell apart: Streak differs, so Lavoisierite leaves white, Braunite leaves brownish black to steel-gray; luster reads vitreous on Lavoisierite and submetallic on Braunite.
Often found alongside lavoisierite
Minerals reported to co-occur with lavoisierite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn₈[Al₁₀(MnMg)][Si₁₁P]O₄₄(OH)₁₂
- Mohs hardness
- 6-7
- Density
- 3.576 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In piemontite-bearing mica schists related to the Alpine tectono-metamorphism of (Mn, Al)-rich sediments
Where rockhounds find lavoisierite
Classic worldwide localities
- Punta Gensane, Viù Valley, Piedmont, Western Alps, Italy
Field-hunting tip
Where it forms: In piemontite-bearing mica schists related to the Alpine tectono-metamorphism of (Mn, Al)-rich sediments. If you start seeing quartz, mica, sursassite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lavoisierite?+
Where is lavoisierite found?+
What rocks look like lavoisierite?+
What minerals are found with lavoisierite?+
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Find lavoisierite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
