Zincrosasite is a rare zinc-dominant member of the rosasite group, typically found as attractive, spherical, or botryoidal crusts. It is best identified by its vibrant blue to greenish-blue color and its occurrence in oxidized ore zones alongside other secondary zinc minerals. Specimens are highly sought after by collectors of Tsumeb or Mexican minerals due to their distinctive morphology and color.
Is this zincrosasite?
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 zincrosasite with a known reference. Zincrosasite sits at Mohs 1, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale blue.
- 3Read the lusterHold the specimen under a strong light. Luster: subadamantine.
- 4Match the color rangeCompare against the expected color range: white, white green, light green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: botryoidal, fibrous, spherulitic aggregates.
Often confused with
Zincrosasite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Rosasite is the harder of the two (Mohs 4.5 vs. 1); streak differs, so Zincrosasite leaves pale blue, Rosasite leaves light blue; luster reads subadamantine on Zincrosasite and vitreous to silky on Rosasite.
How to tell apart: Streak differs, so Zincrosasite leaves pale blue, Aurichalcite leaves light blue; luster reads subadamantine on Zincrosasite and silky to pearly on Aurichalcite.
How to tell apart: Malachite is the harder of the two (Mohs 3.5-4 vs. 1); luster reads subadamantine on Zincrosasite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
Often found alongside zincrosasite
Minerals reported to co-occur with zincrosasite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Zn,Cu)₂(CO₃)(OH)₂
- Mohs hardness
- 1
- Density
- 4-4.2 g/cm³
- Colors
- Streak
- Pale blue
- Luster
- Subadamantine
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Botryoidal, fibrous, spherulitic aggregates
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In an oxidized zone of a dolostone-hosted hydrothermal polymetallic ore deposit (Tsumeb, Namibia)
Where rockhounds find zincrosasite
Classic worldwide localities
- Tsumeb, Namibia
- Rudabanya, Hungary
- Kamariza mine, Laurium, Greece
Field-hunting tip
Where it forms: In an oxidized zone of a dolostone-hosted hydrothermal polymetallic ore deposit (Tsumeb, Namibia). If you start seeing azurite, cerussite, hemimorphite in float, you are in the right ground. Typical habit: botryoidal, fibrous, spherulitic aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify zincrosasite?+
Where is zincrosasite found?+
Is zincrosasite safe to handle?+
What rocks look like zincrosasite?+
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Find zincrosasite on the map
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