Kësterite is a rare copper zinc tin sulfide mineral typically found in tin-bearing hydrothermal deposits. It is often indistinguishable from stannite in hand samples without laboratory analysis, generally appearing as opaque, dark metallic masses.
Is this kësterite?
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 kësterite with a known reference. Kësterite 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. Kësterite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Kësterite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: brown, brownish-black, black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: massive, granular, or anhedral grains.
Often confused with
Kësterite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Kësterite leaves black, Sphalerite leaves white to yellow-brown; luster reads metallic on Kësterite and resinous to submetallic on Sphalerite.
How to tell apart: Streak differs — Kësterite leaves black, Chalcopyrite leaves greenish-black.
Often found alongside kësterite
Minerals reported to co-occur with kësterite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂ZnSnS₄
- Mohs hardness
- 3.5
- Density
- 4.55 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Massive, Granular, Or Anhedral Grains
- Cleavage
- Indistinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Tin-bearing Veins
- Typical price
- $20-150 for small specimens
Where rockhounds find kësterite
Classic worldwide localities
- Kester deposit, Russia
- Bolivia
- Czech Republic
- Japan
Field-hunting tip
Look in hydrothermal tin-bearing veins country — that is the host setting where kësterite typically forms. If you start seeing stannite, sphalerite, chalcopyrite in float, you are in the right ground. Field specimens usually show a massive, granular, or anhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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How much is kësterite worth?+
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Find kësterite on the map
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