Ruthenarsenite is a rare ruthenium arsenide mineral typically found as small, metallic grains within platinum group mineral deposits. Collectors usually find it alongside other rare palladium and platinum minerals in specific geological settings like the Stillwater Complex. Due to its rarity, it is almost exclusively a specimen of interest for advanced mineralogists.
Is this ruthenarsenite?
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 ruthenarsenite with a known reference. Ruthenarsenite sits at Mohs 6-6.5, 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: brown, brownish gray, reddish gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: inclusions.
Often confused with
Ruthenarsenite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside ruthenarsenite
Minerals reported to co-occur with ruthenarsenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ru,Ni)As
- Mohs hardness
- 6-6.5
- Density
- 10 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Inclusions
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As inclusions in Os–Ir–Ru alloys (Papua New Guinea), and in Alpine-type ultramafics
Where rockhounds find ruthenarsenite
Classic worldwide localities
- Anduo, Tibet, China
- Onverwacht mine, on the Merensky Reef, Bushveld complex, Transvaal, South Africa
Field-hunting tip
Where it forms: As inclusions in Os–Ir–Ru alloys (Papua New Guinea), and in Alpine-type ultramafics. If you start seeing rutheniridosmine, irarsite, iridarsenite in float, you are in the right ground. Typical habit: inclusions. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ruthenarsenite?+
Where is ruthenarsenite found?+
Is ruthenarsenite safe to handle?+
What rocks look like ruthenarsenite?+
What minerals are found with ruthenarsenite?+
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Find ruthenarsenite on the map
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