Calcioandyrobertsite is an extremely rare arsenate mineral characterized by its delicate bladed crystal habits and pale blue coloration. It is primarily found in the secondary oxidation zones of complex hydrothermal arsenic-bearing deposits, most notably associated with the world-famous Tsumeb Mine. It is a highly sought-after species for advanced collectors of rare arsenate minerals due to its complex crystal structure and scarcity.
Is this calcioandyrobertsite?
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 calcioandyrobertsite with a known reference. Calcioandyrobertsite sits at Mohs 3, 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: electric blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, radial aggregates.
Often confused with
Calcioandyrobertsite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside calcioandyrobertsite
Minerals reported to co-occur with calcioandyrobertsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KCaCu₅(AsO₄)₄[As(OH)₂O₂]·2H₂O
- Mohs hardness
- 3
- Density
- 4.011 g/cm³
- Colors
- Electric blue
- Streak
- Pale blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed crystals, radial aggregates
- Cleavage
- Good on (100)
- Rarity
- Rare
- Uses
- Collector
- Host rock
- On a single specimen from a weathered polymetallic mineral deposit
Where rockhounds find calcioandyrobertsite
Classic worldwide localities
- Tsumeb mine, Namibia
Field-hunting tip
Where it forms: On a single specimen from a weathered polymetallic mineral deposit. If you start seeing cuprian adamite, zincian olivenite, andyrobertsite in float, you are in the right ground. Typical habit: bladed crystals, radial aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify calcioandyrobertsite?+
Where is calcioandyrobertsite found?+
Is calcioandyrobertsite safe to handle?+
What rocks look like calcioandyrobertsite?+
What minerals are found with calcioandyrobertsite?+
What kind of rock does calcioandyrobertsite form in?+
What is calcioandyrobertsite used for?+
Find calcioandyrobertsite on the map
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