Braithwaiteite is an exceptionally rare arsenate mineral discovered in the Braithwaite mine in the English Lake District. It typically forms as small, bright yellow prismatic crystals in weathered arsenic-rich hydrothermal veins. Collectors prize it for its extremely limited geographic distribution.
Is this braithwaiteite?
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 braithwaiteite with a known reference. Braithwaiteite 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. Braithwaiteite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Braithwaiteite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-orange.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals.
Often confused with
Braithwaiteite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Cornubite is the harder of the two (Mohs 3-4 vs. 2); streak differs — Braithwaiteite leaves yellow, Cornubite leaves pale green.
How to tell apart: Olivenite is the harder of the two (Mohs 3 vs. 2); streak differs — Braithwaiteite leaves yellow, Olivenite leaves olive-green; luster reads vitreous on Braithwaiteite and adamantine on Olivenite.
Often found alongside braithwaiteite
Minerals reported to co-occur with braithwaiteite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₅(AsO₄)₂F₄·7H₂O
- Mohs hardness
- 2
- Density
- 3.31 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $100-500 thumbnail
Where rockhounds find braithwaiteite
Classic worldwide localities
- Braithwaite mine, Cumbria, England
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where braithwaiteite typically forms. If you start seeing arsenopyrite, goethite, quartz in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find braithwaiteite on the map
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