Bulachite is a rare secondary mineral typically found as delicate, radiating sprays or crusts of white, pearly blades in oxidized arsenic deposits. Because of its rarity and fragile crystal habit, it is almost exclusively sought after by advanced micromount collectors who search for it in classic European mining districts.
Is this bulachite?
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 bulachite with a known reference. Bulachite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: satiny.
- 4Match the color rangeCompare against the expected color range: white, colorless, light green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular, radial.
Often confused with
Bulachite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Scorodite is the harder of the two (Mohs 3.5-4 vs. ~2); streak differs, so Bulachite leaves white, Scorodite leaves greenish white; luster reads satiny on Bulachite and vitreous to subadamantine, subresinous on Scorodite.
How to tell apart: Streak differs, so Bulachite leaves white, Pharmacosiderite leaves yellowish green; luster reads satiny on Bulachite and adamantine to greasy on Pharmacosiderite.
Often found alongside bulachite
Minerals reported to co-occur with bulachite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₆(AsO₄)₃(OH)₉(H₂O)₄·2H₂O
- Mohs hardness
- ~2
- Density
- 2.60 g/cm³
- Streak
- White
- Luster
- Satiny
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular, radial
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Initially found on two museum specimens collected on mine dumps
Where rockhounds find bulachite
Classic worldwide localities
- Neubulach, Black Forest, Germany
Field-hunting tip
Where it forms: Initially found on two museum specimens collected on mine dumps. If you start seeing arsenocrandallite, malachite, azurite in float, you are in the right ground. Typical habit: acicular, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bulachite?+
Where is bulachite found?+
Is bulachite safe to handle?+
What rocks look like bulachite?+
What minerals are found with bulachite?+
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Find bulachite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
