Wilhelmramsayite is a very rare copper iron sulfide mineral found primarily in alkaline igneous environments. It typically occurs as small, black, tabular crystals or coatings associated with minerals like aegirine and nepheline in rare-earth rich pegmatites.
Is this wilhelmramsayite?
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 wilhelmramsayite with a known reference. Wilhelmramsayite sits at Mohs 2.5, 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: dark lead gray, iron black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy, tabular.
Often confused with
Wilhelmramsayite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside wilhelmramsayite
Minerals reported to co-occur with wilhelmramsayite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃FeS₃·2H₂O
- Mohs hardness
- 2.5
- Density
- 2.75 g/cm³
- Colors
- Dark lead grayIron black
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Platy, tabular
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- A late hydrothermal phase in the core of an ultra-agpaitic pegmatite dominated by aegirine, microcline, sodalite, natrolite, pectolite, villaumite, ± natrite, thermonatrite, lomonosovite
Where rockhounds find wilhelmramsayite
Classic worldwide localities
- Koashva Quarry, Mt. Koashva, Khibiny massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: A late hydrothermal phase in the core of an ultra-agpaitic pegmatite dominated by aegirine, microcline, sodalite, natrolite, pectolite, villaumite, ± natrite, thermonatrite, lomonosovite. If you start seeing villaumite, pectolite, rasvumite in float, you are in the right ground. Typical habit: platy, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify wilhelmramsayite?+
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Is wilhelmramsayite safe to handle?+
What rocks look like wilhelmramsayite?+
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Find wilhelmramsayite on the map
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