Tochilinite is a rare, complex mineral consisting of alternating layers of iron sulfide and magnesium-iron hydroxide. It is typically found in serpentinized ultramafic environments, often appearing as dark, metallic, flexible flakes or thin coatings on other minerals like magnetite.
Is this tochilinite?
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 tochilinite with a known reference. Tochilinite sits at Mohs 1.5-2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tochilinite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Tochilinite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, bronze-brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy, foliated, or as thin flexible sheets and radiating clusters.
Often confused with
Tochilinite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside tochilinite
Minerals reported to co-occur with tochilinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₅₊ₓS₆(Mg,Fe)₉(OH)₁₈
- Mohs hardness
- 1.5-2
- Density
- 2.7-2.8 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Triclinic
- Crystal habit
- Platy, Foliated, Or as Thin Flexible Sheets and Radiating Clusters
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Altered Ultramafic Rocks and Serpentinized Zones
- Typical price
- $20-150 for rare specimen thumbnails
Where rockhounds find tochilinite
Classic worldwide localities
- Kovdor Massif (Russia)
- Eden Mills (Vermont, USA)
- Musonoi Mine (DRC)
- Mount Vesuvius (Italy)
Field-hunting tip
Look in altered ultramafic rocks and serpentinized zones country — that is the host setting where tochilinite typically forms. If you start seeing serpentine, magnetite, calcite in float, you are in the right ground. Field specimens usually show a platy, foliated, or as thin flexible sheets and radiating clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tochilinite?+
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How much is tochilinite worth?+
What rocks look like tochilinite?+
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Find tochilinite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
