Braithwaiteite is a rare sodium copper antimony arsenate, typically sky-blue. It is an uncommon secondary mineral in the weathering zone of a hydrothermal enargite deposit. It is associated with lammerite and lavendulan-lemmereite. It was first described from Laurani, near Sica Sica, Bolivia.
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. Streak: pale blue.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: sky-blue.
- 5Look at form & habitCrystal system: triclinic. 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 ~4 vs. ~2).
How to tell apart: Olivenite is the harder of the two (Mohs 3 vs. ~2); streak differs, so Braithwaiteite leaves pale blue, Olivenite leaves olive-green to brown; luster reads vitreous on Braithwaiteite and adamantine to vitreous, pearly to silky if fibrous 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
- NaCu²⁺₅(Sb⁵⁺Ti⁴⁺)O₂(AsO₄)₄[AsO₃(OH)]₂·8H₂O
- Mohs hardness
- ~2
- Density
- 3.44 g/cm³
- Colors
- Streak
- Pale blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Prismatic crystals
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon secondary mineral in the weathering zone of a hydrothermal enargite deposit
Where rockhounds find braithwaiteite
Classic worldwide localities
- Laurani, near Sica Sica, Bolivia
Field-hunting tip
Where it forms: An uncommon secondary mineral in the weathering zone of a hydrothermal enargite deposit. If you start seeing lammerite, lavendulan-lemmereite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify braithwaiteite?+
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What rocks look like braithwaiteite?+
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Find braithwaiteite on the map
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