Weilite is a rare calcium arsenate mineral typically found as small, thin tabular crystals in hydrothermal deposits. It is structurally related to the monetite group and is primarily prized by advanced mineral collectors for its scarcity and aesthetic crystal form.
Is this weilite?
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 weilite with a known reference. Weilite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: porcelaneous, may be greasy to slightly pearly.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: triclinic. Typical habit: encrustations, powdery.
Often confused with
Weilite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads porcelaneous, may be greasy to slightly pearly on Weilite and vitreous on Monetite.
How to tell apart: Luster reads porcelaneous, may be greasy to slightly pearly on Weilite and vitreous, pearly on cleavages on Pharmacolite.
Often found alongside weilite
Minerals reported to co-occur with weilite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaHAsO₄
- Mohs hardness
- 2-3
- Density
- 3.48 g/cm³
- Colors
- Streak
- White
- Luster
- Porcelaneous, may be greasy to slightly pearly
- Transparency
- Semitransparent
- Crystal system
- Triclinic
- Crystal habit
- Encrustations, powdery
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in the oxidized zone of arsenic-bearing hydrothermal mineral deposits
Where rockhounds find weilite
Classic worldwide localities
- Getchell mine, Humboldt Co., Nevada, USA
- Schneeberg, at the Daniel mine, and at Schlema-Hartenstein, Saxony, Germany
- Wittichen, Black Forest, Germany
- Bauhaus district, Richelsdorf Mountains, Hesse, Germany
- Gabe-Gottes mine, Rauenthal, near Sainte-Marie-aux-Mines, Haut-Rhin, and at Duranus, Alpes-Maritimes, France
- Wanthwaite mine, St. John’s in the Vale, Cumbria, England
Field-hunting tip
Where it forms: A rare secondary mineral in the oxidized zone of arsenic-bearing hydrothermal mineral deposits. If you start seeing pharmacolite, haidingerite, picropharmacolite in float, you are in the right ground. Typical habit: encrustations, powdery. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify weilite?+
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Is weilite safe to handle?+
What rocks look like weilite?+
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Find weilite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
