Pentlandite is the primary source of nickel and typically occurs in granular or massive aggregates within sulfide ore bodies. It is easily recognized by its distinct bronze-yellow color and tendency to be found in close association with magnetic pyrrhotite. Collectors often prize specimens from the major nickel-copper mining districts like Sudbury.
Is this pentlandite?
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 pentlandite with a known reference. Pentlandite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pentlandite leaves a light bronze-brown streak.
- 3Read the lusterHold the specimen under a strong light. Pentlandite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: bronze-yellow, brownish-yellow.
- 5Look at form & habitCrystal system: cubic. Typical habit: granular, massive, rarely as octahedral crystals.
Often confused with
Pentlandite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Pentlandite leaves light bronze-brown, Pyrrhotite leaves dark grey to black.
How to tell apart: Streak differs — Pentlandite leaves light bronze-brown, Chalcopyrite leaves greenish-black.
How to tell apart: Pyrite is the harder of the two (Mohs 6-6.5 vs. 3.5-4); streak differs — Pentlandite leaves light bronze-brown, Pyrite leaves greenish-black to brownish-black.
Often found alongside pentlandite
Minerals reported to co-occur with pentlandite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Fe,Ni)₉S₈
- Mohs hardness
- 3.5-4
- Density
- 4.6-5.0 g/cm³
- Streak
- Light Bronze-brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Granular, Massive, Rarely as Octahedral Crystals
- Cleavage
- None
- Rarity
- Common
- Uses
- Industrial, Ore of Nickel, Collector
- Host rock
- Mafic and Ultramafic Igneous Rocks
- Typical price
- $10-60 for small mineral specimens
Where rockhounds find pentlandite
Classic worldwide localities
- Sudbury, Ontario, Canada
- Norilsk, Russia
- Bushveld Complex, South Africa
- Kambalda, Australia
- Voisey's Bay, Canada
Field-hunting tip
Look in mafic and ultramafic igneous rocks country — that is the host setting where pentlandite typically forms. If you start seeing pyrrhotite, chalcopyrite, magnetite in float, you are in the right ground. Field specimens usually show a granular, massive, rarely as octahedral crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find pentlandite on the map
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