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, 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.
