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 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hongshiite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hongshiite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: white, pale yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: irregular grains, inclusions.
Often confused with
Hongshiite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Cooperite is the harder of the two (Mohs 4-5 vs. 2.5-3); streak differs, so Hongshiite leaves white, Cooperite leaves black.
How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 2.5-3); streak differs, so Hongshiite leaves white, Sperrylite leaves black.
How to tell apart: Platinum is the harder of the two (Mohs 4-4.5 vs. 2.5-3); streak differs, so Hongshiite leaves white, Platinum leaves steel-gray.
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
- 2.5-3
- Density
- 15.7-16.0 g/cm³
- Colors
- Streak
- White
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Irregular Grains, Inclusions
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Ultramafic Igneous Rocks
- Typical price
- $100-500 thumbnail
Where rockhounds find hongshiite
Classic worldwide localities
- Hongshi-la, China
- Stillwater Complex, USA
- Bushveld Complex, South Africa
Field-hunting tip
Look in ultramafic igneous rocks country, the host setting where hongshiite typically forms. If you start seeing platinum, palladium, chalcopyrite in float, you are in the right ground. Field specimens usually show a irregular grains, inclusions habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find hongshiite on the map
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