Hongshiite is a rare platinum-copper alloy typically found as minute grains or inclusions within sulfide deposits. It is best identified through laboratory analysis such as electron microprobe or X-ray diffraction due to its microscopic habit and resemblance to other platinum-group minerals.
Is this hongshiite?
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 hongshiite with a known reference. Hongshiite 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: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: lead gray, bronze.
- 5Look at form & habitCrystal system: trigonal. Typical habit: microscopic crystals.
Often confused with
Hongshiite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside hongshiite
Minerals reported to co-occur with hongshiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PtCu
- Mohs hardness
- 4
- Density
- 15.71 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Microscopic crystals
- Cleavage
- On {1011}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In an actinolized diopside-type of platinum deposit (China); in high-grade hematitic veins in itabirite, typically rimmed by platinum from which copper has been leached (Brazil)
Where rockhounds find hongshiite
Classic worldwide localities
- Fox Gulch, Goodnews Bay, Alaska, USA
- A placer in the Upper Miask River, Southern Ural Mountains, Russia
- Konder massif, Aldan Shield, Sakha, Russia
- Placers on the Pustaya River, Kamchatka, Russia
- A placer on the North Saskatchewan River, near Edmonton, Alberta, Canada
- Placers along the Santiago River, Esmeraldas Province, Ecuador
Field-hunting tip
Where it forms: In an actinolized diopside-type of platinum deposit (China); in high-grade hematitic veins in itabirite, typically rimmed by platinum from which copper has been leached (Brazil). If you start seeing cooperite, sperrylite, vysotskite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hongshiite?+
Where is hongshiite found?+
Is hongshiite safe to handle?+
What rocks look like hongshiite?+
What minerals are found with hongshiite?+
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Find hongshiite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
