Arsenogoyazite is a rare member of the alunite supergroup typically found as small, rhombohedral crystals in the oxidation zones of arsenic-rich ore deposits. Collectors primarily seek this mineral from world-class localities like the Tsumeb Mine, where it forms in association with other rare arsenate minerals.
Is this arsenogoyazite?
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 arsenogoyazite with a known reference. Arsenogoyazite sits at Mohs ~4, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: greenish white, gray green, yellow, light green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: encrustations, reniform.
Often confused with
Arsenogoyazite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside arsenogoyazite
Minerals reported to co-occur with arsenogoyazite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SrAl₃(AsO₄)(AsO₃OH)(OH)₆
- Mohs hardness
- ~4
- Density
- 3.35 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Encrustations, reniform
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral in a hydrothermal polymetallic barite–fluorite deposit (Clara mine, Germany)
Where rockhounds find arsenogoyazite
Classic worldwide localities
- Centennial Eureka mine, Tintic district, Juab Co., Utah, USA
- Clara Mine, near Oberwolfach, Black Forest, Germany
Field-hunting tip
Where it forms: A secondary mineral in a hydrothermal polymetallic barite–fluorite deposit (Clara mine, Germany). If you start seeing olivenite, cornwallite, malachite in float, you are in the right ground. Typical habit: encrustations, reniform. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify arsenogoyazite?+
Where is arsenogoyazite found?+
Is arsenogoyazite safe to handle?+
What rocks look like arsenogoyazite?+
What minerals are found with arsenogoyazite?+
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Find arsenogoyazite on the map
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