Zemannite is a rare tellurite mineral typically found as small, bright yellow prismatic to acicular crystals. It is primarily known from oxidized zones of tellurium-rich ore deposits, often appearing as coatings or drusy aggregates on rock surfaces.
Is this zemannite?
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 zemannite with a known reference. Zemannite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Zemannite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Zemannite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish-yellow, golden-yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: prismatic to acicular crystals.
Often confused with
Zemannite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Zemannite is noticeably harder (Mohs 3 vs. 2); streak differs — Zemannite leaves yellow, Cesbronite leaves light green.
How to tell apart: Emmonsite is the harder of the two (Mohs 5 vs. 3); streak differs — Zemannite leaves yellow, Emmonsite leaves pale yellow.
Often found alongside zemannite
Minerals reported to co-occur with zemannite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₀.₅ZnFe³⁺(TeO₃)₃·4.5H₂O
- Mohs hardness
- 3
- Density
- 3.84 g/cm³
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Prismatic to Acicular Crystals
- Cleavage
- Distinct On {10-10}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Tellurium-bearing Hydrothermal Deposits
- Typical price
- $100-500+ per specimen depending on size and crystal quality
Where rockhounds find zemannite
Classic worldwide localities
- Moctezuma mine, Sonora, Mexico
- La Virgen mine, San Luis Potosí, Mexico
Field-hunting tip
Look in oxidized tellurium-bearing hydrothermal deposits country — that is the host setting where zemannite typically forms. If you start seeing quetzalcoatlite, spiridonovite, tellurite in float, you are in the right ground. Field specimens usually show a prismatic to acicular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find zemannite on the map
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