Ottemannite is a rare tin sulfide mineral typically occurring as small, vibrant yellow to orange-yellow tabular crystals. It is most frequently found in hydrothermal vein systems associated with other tin minerals like stannite and cassiterite. Collectors should look for these bright, resinous crystals within sulfide-rich mineral assemblages in tin-bearing deposits.
Is this ottemannite?
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 ottemannite with a known reference. Ottemannite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: reddish gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: lath.
Often confused with
Ottemannite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ottemannite leaves yellow, Orpiment leaves pale lemon-yellow; luster reads metallic on Ottemannite and resinous, pearly on cleavage surface on Orpiment.
How to tell apart: Greenockite is the harder of the two (Mohs 3-3.5 vs. ~2); streak differs, so Ottemannite leaves yellow, Greenockite leaves yellow-orange to brick-red; luster reads metallic on Ottemannite and adamantine to resinous on Greenockite.
How to tell apart: Stannite is the harder of the two (Mohs 4 vs. ~2); streak differs, so Ottemannite leaves yellow, Stannite leaves blackish.
Often found alongside ottemannite
Minerals reported to co-occur with ottemannite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Sn₂S₃
- Mohs hardness
- ~2
- Density
- 4.87 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Lath
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector, Reference material
- Host rock
- In zones of oxidation or secondary enrichment in hydrothermal tin deposits
Where rockhounds find ottemannite
Classic worldwide localities
- Cerro Rico, Potosí (type locality) and at the Maria-Teresa mine, near Huari, between Oruro and Uyuni, Bolivia
- Stiepelmann mine, near Arandis, Namibia
Field-hunting tip
Where it forms: In zones of oxidation or secondary enrichment in hydrothermal tin deposits. If you start seeing stannite, cassiterite, herzenbergite 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 ottemannite on the map
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