Rosasite is a secondary mineral often found as attractive blue to blue-green botryoidal crusts or fibrous aggregates in oxidized copper-zinc mines. It is visually similar to malachite and aurichalcite, requiring careful testing to distinguish it from other copper carbonates.
Is this rosasite?
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 rosasite with a known reference. Rosasite 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. Rosasite leaves a light blue streak.
- 3Read the lusterHold the specimen under a strong light. Rosasite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: blue, green, blue-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: botryoidal, crusts, radial aggregates.
Often confused with
Rosasite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Rosasite leaves light blue, Malachite leaves light green; luster reads pearly on Rosasite and vitreous on Malachite.
How to tell apart: Rosasite is noticeably harder (Mohs 4 vs. 2); streak differs — Rosasite leaves light blue, Aurichalcite leaves pale blue.
How to tell apart: Streak differs — Rosasite leaves light blue, Chrysocolla leaves white; luster reads pearly on Rosasite and vitreous on Chrysocolla.
Often found alongside rosasite
Minerals reported to co-occur with rosasite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Cu,Zn)₂(CO₃)(OH)₂
- Mohs hardness
- 4
- Density
- 4.0-4.2 g/cm³
- Colors
- Streak
- Light Blue
- Luster
- Pearly
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Botryoidal, Crusts, Radial Aggregates
- Cleavage
- Perfect On {010}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper-zinc Deposits
- Typical price
- $10-100 per specimen
Where rockhounds find rosasite
Classic worldwide localities
- Rosas mine, Italy
- Ojuela mine, Mexico
- Tsumeb, Namibia
- Arizona, USA
Field-hunting tip
Look in oxidized zones of copper-zinc deposits country — that is the host setting where rosasite typically forms. If you start seeing aurichalcite, smithsonite, malachite in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify rosasite?+
Where is rosasite found?+
How much is rosasite worth?+
Is rosasite safe to handle?+
What rocks look like rosasite?+
What minerals are found with rosasite?+
What kind of rock does rosasite form in?+
What is rosasite used for?+
Find rosasite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
