Orthowalpurgite is an extremely rare secondary bismuth arsenate mineral found in the oxidation zones of uranium-bismuth deposits. It typically occurs as minute, thin tabular crystals or radial clusters that are easily mistaken for the triclinic mineral walpurgite. Collectors primarily find this species as micro-specimens associated with other rare bismuth minerals.
Is this orthowalpurgite?
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 orthowalpurgite with a known reference. Orthowalpurgite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Orthowalpurgite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Orthowalpurgite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: yellow, orange-yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals, radial aggregates.
Often confused with
Orthowalpurgite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Orthowalpurgite leaves yellow, Walpurgite leaves yellowish.
How to tell apart: Streak differs — Orthowalpurgite leaves yellow, Mixite leaves white; luster reads adamantine on Orthowalpurgite and vitreous on Mixite.
How to tell apart: Streak differs — Orthowalpurgite leaves yellow, Atelestite leaves white.
Often found alongside orthowalpurgite
Minerals reported to co-occur with orthowalpurgite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (BiO)₄(AsO₄)₂(OH)₂
- Mohs hardness
- 3-4
- Density
- 6.2 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals, Radial Aggregates
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Uranium-bismuth Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find orthowalpurgite
Classic worldwide localities
- Schneeberg, Saxony, Germany
- Jáchymov, Czech Republic
Field-hunting tip
Look in hydrothermal uranium-bismuth deposits country — that is the host setting where orthowalpurgite typically forms. If you start seeing walpurgite, mixite, bismutite in float, you are in the right ground. Field specimens usually show a tabular crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify orthowalpurgite?+
Where is orthowalpurgite found?+
How much is orthowalpurgite worth?+
Is orthowalpurgite safe to handle?+
What rocks look like orthowalpurgite?+
What minerals are found with orthowalpurgite?+
What kind of rock does orthowalpurgite form in?+
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Find orthowalpurgite on the map
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