Astrocyanite-(Ce) is a rare copper-cerium carbonate mineral known almost exclusively from the nepheline syenite pegmatites of Mont Saint-Hilaire. It typically forms striking, vibrant blue, thin platy crystals that occur in radiating rosettes or aggregate clusters.
Is this astrocyanite-(ce)?
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 astrocyanite-(ce) with a known reference. Astrocyanite-(Ce) sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: bluish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: blue, bright blue, blue green.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: rosette, stellate, tabular.
Often confused with
Astrocyanite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside astrocyanite-(ce)
Minerals reported to co-occur with astrocyanite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂Ce₂(UO₂)(CO₃)₅(OH)₂·1.5H₂O
- Mohs hardness
- 2-3
- Density
- 3.80 g/cm³
- Streak
- Bluish white
- Luster
- Vitreous
- Transparency
- Translucent to opaque
- Crystal system
- Hexagonal
- Crystal habit
- Rosette, stellate, tabular
- Cleavage
- On {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidation zone of the uranium-bearing portion of a Cu–Co deposit
Where rockhounds find astrocyanite-(ce)
Classic worldwide localities
- Kamoto-East Cu–Co mine, five km west of Kolwezi, Katanga Province, Congo (Shaba Province, Zaire)
Field-hunting tip
Where it forms: In the oxidation zone of the uranium-bearing portion of a Cu–Co deposit. If you start seeing uraninite, uranophane, kamotoite- in float, you are in the right ground. Typical habit: rosette, stellate, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify astrocyanite-(ce)?+
Where is astrocyanite-(ce) found?+
Is astrocyanite-(ce) safe to handle?+
What rocks look like astrocyanite-(ce)?+
What minerals are found with astrocyanite-(ce)?+
What kind of rock does astrocyanite-(ce) form in?+
What is astrocyanite-(ce) used for?+
Find astrocyanite-(ce) on the map
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