Moncheite is a rare platinum group telluride mineral that typically occurs as microscopic inclusions within massive sulfide ore bodies. Collectors usually find this mineral as part of polished ore assemblages from major platinum-producing districts like the Stillwater or Bushveld complexes. Identification generally requires microscopic study or chemical analysis due to its small grain size and similarity to other platinum-group sulfides.
Is this moncheite?
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 moncheite with a known reference. Moncheite sits at Mohs 2-3, 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: steel gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: inclusions, microscopic crystals.
Often confused with
Moncheite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Kotulskite is the harder of the two (Mohs 4-4.5 vs. 2-3); streak differs, so Moncheite leaves gray, Kotulskite leaves black.
How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 2-3); streak differs, so Moncheite leaves gray, Sperrylite leaves black.
Often found alongside moncheite
Minerals reported to co-occur with moncheite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pt(Te,Bi)₂
- Mohs hardness
- 2-3
- Density
- 10 g/cm³
- Colors
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Inclusions, microscopic crystals
- Cleavage
- On {0001}
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- Typically in small amounts in Pt–Pd-bearing massive Cu–Ni sulfide deposits
Where rockhounds find moncheite
Classic worldwide localities
- Stillwater complex, Montana, USA
- New Rambler Cu–Ni mine, Medicine Bow Mountains, east of Encampment, Albany Co., Wyoming, USA
- Key West mine, east of Moapa, Bunkerville district, Clark Co., Nevada, USA
- Gravels of the San Joaquin River, at Friant, Fresno Co., California, USA
- Monchegorsk deposit, Monche Tundra, Kola Peninsula (type locality), Russia
- Oktyabr mine, Noril’sk region, western Siberia, Russia
Field-hunting tip
Where it forms: Typically in small amounts in Pt–Pd-bearing massive Cu–Ni sulfide deposits. If you start seeing merenskyite, melonite, sobolevskite in float, you are in the right ground. Typical habit: inclusions, microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify moncheite?+
Where is moncheite found?+
Is moncheite safe to handle?+
What rocks look like moncheite?+
What minerals are found with moncheite?+
What kind of rock does moncheite form in?+
What is moncheite used for?+
Find moncheite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
