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, so Braithwaiteite leaves yellow, Cornubite leaves pale green.
How to tell apart: Olivenite is the harder of the two (Mohs 3 vs. 2); streak differs, so 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, 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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