Feinglosite is an extremely rare secondary mineral known almost exclusively from the Tsumeb Mine in Namibia. It typically forms as small, elongated pale olive-green prismatic crystals within the oxidation zones of polymetallic ore deposits.
Is this feinglosite?
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 feinglosite with a known reference. Feinglosite 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: adamantine.
- 4Match the color rangeCompare against the expected color range: pale olive green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Feinglosite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Feinglosite leaves white, Duftite leaves pale green to white; luster reads adamantine on Feinglosite and dull to vitreous on fractures on Duftite.
How to tell apart: Luster reads adamantine on Feinglosite and resinous to subadamantine on Mimetite.
Often found alongside feinglosite
Minerals reported to co-occur with feinglosite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂Zn(AsO₄)₂·H₂O
- Mohs hardness
- 4-5
- Density
- 6.52 g/cm³
- Colors
- Pale olive green
- Streak
- White
- Luster
- Adamantine
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals
- Cleavage
- Distinct on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A very rare secondary mineral, in a cavity in chalcocite, from an oxidized zone in a dolostone-hosted hydrothermal polymetallic ore deposit
Where rockhounds find feinglosite
Classic worldwide localities
- Tsumeb, Namibia
Field-hunting tip
Where it forms: A very rare secondary mineral, in a cavity in chalcocite, from an oxidized zone in a dolostone-hosted hydrothermal polymetallic ore deposit. If you start seeing goethite, anglesite, wulfenite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find feinglosite on the map
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