Argentopentlandite is a rare silver-bearing sulfide mineral that typically occurs as anhedral grains within nickel-copper ore deposits. Collectors identify it primarily by its characteristic bronze-yellow metallic luster and its common association with other massive sulfide ores in igneous complexes.
Is this argentopentlandite?
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 argentopentlandite with a known reference. Argentopentlandite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: reddish brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: bronze brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: massive, granular.
Often confused with
Argentopentlandite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Argentopentlandite leaves reddish brown, Pentlandite leaves pale bronze-brown.
How to tell apart: Streak differs, so Argentopentlandite leaves reddish brown, Pyrrhotite leaves dark grayish black.
How to tell apart: Streak differs, so Argentopentlandite leaves reddish brown, Chalcopyrite leaves greenish black.
Often found alongside argentopentlandite
Minerals reported to co-occur with argentopentlandite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag(Fe,Ni)₈S₈
- Mohs hardness
- 3.5
- Density
- 4.66 g/cm³
- Colors
- Streak
- Reddish brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Massive, granular
- Cleavage
- Well developed on {111}
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In pyrite and cubanite-chalcopyrite hydrothermal veins in ultramafic rocks and in skarn; in hydrothermal veins in acidic volcanics; rare in carbonatites
Where rockhounds find argentopentlandite
Classic worldwide localities
- Silver City, Ontonogan Co., Michigan, USA
- Oktyabr mine, Talnakh area, Noril’sk region, western Siberia (type locality), and the Khovu-Aksy Co–Ni deposit, Tuva (type locality), Russia
- Vuonos, Miihkali, Hietajärvi, and Outokumpu deposits, Finland
- Talnotry mine, Newton Stewart, Kirkcudbrightshire, Scotland
- El Charcón, Murcia Province, Spain
- Koronuda, Macedonia, Greece
Field-hunting tip
Where it forms: In pyrite and cubanite-chalcopyrite hydrothermal veins in ultramafic rocks and in skarn; in hydrothermal veins in acidic volcanics; rare in carbonatites. If you start seeing pyrite, pyrrhotite, mackinawite in float, you are in the right ground. Typical habit: massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify argentopentlandite?+
Where is argentopentlandite found?+
Is argentopentlandite safe to handle?+
What rocks look like argentopentlandite?+
What minerals are found with argentopentlandite?+
What kind of rock does argentopentlandite form in?+
What is argentopentlandite used for?+
Find argentopentlandite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
