Talnakhite is a rare copper-iron sulfide found primarily in high-grade copper-nickel ore deposits. It is often visually indistinguishable from chalcopyrite in hand specimens without professional laboratory analysis, though it often occurs as part of complex ore mineral assemblages.
Is this talnakhite?
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 talnakhite with a known reference. Talnakhite sits at Mohs 4-4.5, 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: yellow, tarnish pink, tarnish brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: lath.
Often confused with
Talnakhite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Talnakhite leaves black, Chalcopyrite leaves greenish black.
How to tell apart: Talnakhite is noticeably harder (Mohs 4-4.5 vs. 3-3.25); streak differs, so Talnakhite leaves black, Bornite leaves pale grayish black.
Often found alongside talnakhite
Minerals reported to co-occur with talnakhite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₉Fe₈S₁₆
- Mohs hardness
- 4-4.5
- Density
- 4.29 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Lath
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In concentrations of up to 70% in zones to 12 m thick, in hydrothermal ores (Talnakh area, Russia); in the layered ultramafic Stillwater complex (Nye, Montana, USA); a component of undersea black smokers
Where rockhounds find talnakhite
Classic worldwide localities
- Nye, Stillwater Co., Montana, USA
- Norilsk-I (type locality) and Talnakh deposits (type locality), Talnakh area, Noril’sk region, western Siberia, Russia
- Strachimir, Bulgaria
- Filizchai deposit, Azerbaijan
- Axial Rift Valley, Red Sea
- Horoman peridotite, Hokkaido, Japan
Field-hunting tip
Where it forms: In concentrations of up to 70% in zones to 12 m thick, in hydrothermal ores (Talnakh area, Russia); in the layered ultramafic Stillwater complex (Nye, Montana, USA); a component of undersea black smokers. If you start seeing chalcopyrite, cubanite, djerfisherite in float, you are in the right ground. Typical habit: lath. Train your eye for that shape before scanning the outcrop.
Common questions
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Find talnakhite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
