Wattevilleite is a rare hydrated sodium calcium sulfate often found as delicate white fibrous or acicular crusts on mine walls. It is a secondary mineral formed through the oxidation of sulfide ores, typically found in historical mining districts. Due to its solubility, it is rarely seen in field collections and is highly sensitive to humidity levels.
Is this wattevilleite?
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 wattevilleite with a known reference. Wattevilleite 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. Wattevilleite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Wattevilleite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular, fibrous, crusts.
Often confused with
Wattevilleite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside wattevilleite
Minerals reported to co-occur with wattevilleite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Ca(SO₄)₂·4H₂O
- Mohs hardness
- 2
- Density
- 1.79 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular, Fibrous, Crusts
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Ore Deposits, Mine Workings
- Typical price
- $20-100 for small study specimens
Where rockhounds find wattevilleite
Classic worldwide localities
- Haselgebirge, Hallstatt, Austria
- Jáchymov, Czech Republic
- Rio Marina, Elba, Italy
Field-hunting tip
Look in oxidized ore deposits, mine workings country — that is the host setting where wattevilleite typically forms. If you start seeing gypsum, melanterite, pickeringite in float, you are in the right ground. Field specimens usually show a acicular, fibrous, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find wattevilleite on the map
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