Montanite is an uncommon bismuth tellurate mineral typically formed as an alteration product in oxidized tellurium-bearing deposits. It is most frequently encountered as soft, yellow to white earthy crusts or powdery coatings associated with native tellurium and gold.
Is this montanite?
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 montanite with a known reference. Montanite 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. Montanite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Montanite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: yellow, white, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive, earthy, crusts.
Often confused with
Montanite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Montanite is noticeably harder (Mohs 3 vs. 2); luster reads dull on Montanite and adamantine on Tellurite.
How to tell apart: Emmonsite is the harder of the two (Mohs 5 vs. 3); streak differs — Montanite leaves white, Emmonsite leaves pale yellow; luster reads dull on Montanite and vitreous on Emmonsite.
Often found alongside montanite
Minerals reported to co-occur with montanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Bi₂TeO₆·2H₂O
- Mohs hardness
- 3
- Density
- 6.5 g/cm³
- Colors
- Streak
- White
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Massive, Earthy, Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Hydrothermal Tellurium-bearing Veins
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find montanite
Classic worldwide localities
- Montana, USA
- Guanajuato, Mexico
- New South Wales, Australia
Field-hunting tip
Look in oxidized hydrothermal tellurium-bearing veins country — that is the host setting where montanite typically forms. If you start seeing tellurium, gold, quartz in float, you are in the right ground. Field specimens usually show a massive, earthy, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify montanite?+
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How much is montanite worth?+
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Find montanite on the map
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