Arsendescloizite is a rare secondary mineral typically found as small, dull-lustered crusts or rounded aggregates within the oxidized zones of lead-zinc deposits. It is chemically an arsenate analog of descloizite and is frequently found in association with other lead-bearing minerals in classic localities like Tsumeb.
Is this arsendescloizite?
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 arsendescloizite with a known reference. Arsendescloizite sits at Mohs 4-5, 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: subadamantine.
- 4Match the color rangeCompare against the expected color range: light yellow, dark green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crusts, mammillary, or spherical aggregates.
Often confused with
Arsendescloizite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Arsendescloizite leaves white, Descloizite leaves orange to brownish red; luster reads subadamantine on Arsendescloizite and greasy on Descloizite.
How to tell apart: Luster reads subadamantine on Arsendescloizite and resinous to subadamantine on Mimetite.
Often found alongside arsendescloizite
Minerals reported to co-occur with arsendescloizite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbZn(AsO₄)(OH)
- Mohs hardness
- 4-5
- Density
- 5.67 g/cm³
- Colors
- Streak
- White
- Luster
- Subadamantine
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Crusts, mammillary, or spherical aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral in oxidized hydrothermal polymetallic deposits
Where rockhounds find arsendescloizite
Classic worldwide localities
- Silver Coin mine, near Valmy, Iron Point district, Humboldt Co., Nevada, USA
- Tsumeb, Namibia
- Gejiu Pb–Zn deposit, not otherwise located, China
- Toroku mine, Miyazaki Prefecture, Japan
- Ojuela mine, Mapimí, Durango, Mexico
- Michael mine, Weiler, near Lahr, Black Forest, Germany
Field-hunting tip
Where it forms: A secondary mineral in oxidized hydrothermal polymetallic deposits. If you start seeing tennantite, chalcocite, willemite in float, you are in the right ground. Typical habit: crusts, mammillary, or spherical aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
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Find arsendescloizite on the map
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