Orthocuproplatinum is a very rare platinum-copper alloy typically found as minute inclusions within other platinum-group minerals. It is primarily identified through specialized analytical methods like electron microprobe analysis, appearing as small silver-white grains in reflected light under a microscope.
Is this orthocuproplatinum?
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 orthocuproplatinum with a known reference. Orthocuproplatinum sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: white, silver-white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: anhedral grains, inclusions in platinum group minerals.
Often confused with
Orthocuproplatinum vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Isoferroplatinum is the harder of the two (Mohs 5 vs. 4); streak differs, so Orthocuproplatinum leaves gray, Isoferroplatinum leaves grayish-black.
How to tell apart: Tulameenite is the harder of the two (Mohs 5 vs. 4).
Often found alongside orthocuproplatinum
Minerals reported to co-occur with orthocuproplatinum. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pt₃Cu
- Mohs hardness
- 4
- Density
- 18.35 g/cm³
- Colors
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Anhedral grains, inclusions in platinum group minerals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- ultramafic igneous rocks
Where rockhounds find orthocuproplatinum
Classic worldwide localities
- Ioko-Dovyren massif, Russia
- Stillwater complex, USA
- Bushveld complex, South Africa
Field-hunting tip
Where it forms: ultramafic igneous rocks. If you start seeing platinum, cooperite, sperrylite in float, you are in the right ground. Typical habit: anhedral grains, inclusions in platinum group minerals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify orthocuproplatinum?+
Where is orthocuproplatinum found?+
Is orthocuproplatinum safe to handle?+
What rocks look like orthocuproplatinum?+
What minerals are found with orthocuproplatinum?+
What kind of rock does orthocuproplatinum form in?+
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Find orthocuproplatinum on the map
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