Santarosaite is a rare copper oxide that forms vivid blue globules of leaf-like crystals. It occurs in the oxidation zone of a hydrothermal polymetallic vein deposit. Associated minerals include atacamite, malachite and wulfenite. It was first described from Santa Rosa mine, 15 km SE of Iquique, Atacama desert, Northern Chile.
Is this santarosaite?
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 santarosaite with a known reference. Santarosaite sits at Mohs 3.5, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: vivid blue.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: globular.
Often confused with
Santarosaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Santarosaite leaves pale blue, Volborthite leaves light green.
How to tell apart: Streak differs, so Santarosaite leaves pale blue, Mottramite leaves yellowish green; luster reads vitreous on Santarosaite and greasy on Mottramite.
Often found alongside santarosaite
Minerals reported to co-occur with santarosaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CuB₂O₄
- Mohs hardness
- 3.5
- Density
- 3.96 g/cm³
- Colors
- Vivid blue
- Streak
- Pale blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Globular
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidation zone of a hydrothermal polymetallic vein deposit
Where rockhounds find santarosaite
Classic worldwide localities
- Santa Rosa mine, 15 km SE of Iquique, Atacama desert, Northern Chile
Field-hunting tip
Where it forms: In the oxidation zone of a hydrothermal polymetallic vein deposit. If you start seeing atacamite, malachite, wulfenite in float, you are in the right ground. Typical habit: globular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify santarosaite?+
Where is santarosaite found?+
Is santarosaite safe to handle?+
What rocks look like santarosaite?+
What minerals are found with santarosaite?+
What kind of rock does santarosaite form in?+
What is santarosaite used for?+
Find santarosaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
