Coyoteite is a very rare sulfide mineral found as small, black, platy crystals. It is primarily known from the Coyote Peak diatreme in California where it occurs in vugs within alkaline igneous rocks. Collectors typically find it associated with other sulfide minerals in small, specialized mineralogical collections.
Is this coyoteite?
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 coyoteite with a known reference. Coyoteite sits at Mohs ~1.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: triclinic. Typical habit: irregular grains.
Often confused with
Coyoteite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside coyoteite
Minerals reported to co-occur with coyoteite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaFe₃S₅·2H₂O
- Mohs hardness
- ~1.5
- Density
- 2.5-2.63 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Triclinic
- Crystal habit
- Irregular grains
- Cleavage
- Perfect on {111}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- With rare iron sulfides in small pegmatitic clots thought to have crystallized late in the consolidation of the Coyote Peak intrusive, an alkalic mafic diatreme
Where rockhounds find coyoteite
Classic worldwide localities
- Coyote Peak, near Orick, Humboldt Co., California, USA (type locality)
Field-hunting tip
Where it forms: With rare iron sulfides in small pegmatitic clots thought to have crystallized late in the consolidation of the Coyote Peak intrusive, an alkalic mafic diatreme. If you start seeing pyrrhotite, djerfisherite, rasvumite in float, you are in the right ground. Typical habit: irregular grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify coyoteite?+
Where is coyoteite found?+
What rocks look like coyoteite?+
What minerals are found with coyoteite?+
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Find coyoteite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
