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, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Astrocyanite-(Ce) leaves a pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Astrocyanite-(Ce) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: platy crystals, rosettes.
Often confused with
Astrocyanite-(Ce) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Azurite is the harder of the two (Mohs 3.5-4 vs. 2); streak differs, so Astrocyanite-(Ce) leaves pale blue, Azurite leaves light blue; luster reads vitreous on Astrocyanite-(Ce) and vitreous to dull on Azurite.
How to tell apart: Kamphaugite-(Y) is the harder of the two (Mohs 3 vs. 2); streak differs, so Astrocyanite-(Ce) leaves pale blue, Kamphaugite-(Y) leaves white.
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(CO₃)₄(OH)₂·1.5H₂O
- Mohs hardness
- 2
- Density
- 3.8 g/cm³
- Colors
- Streak
- Pale Blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Platy Crystals, Rosettes
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks
Where rockhounds find astrocyanite-(ce)
Classic worldwide localities
- Kamoto-East Cu-Co mine, 5 km west of Kolwezi, Katanga Province, Democratic Republic of Congo
Field-hunting tip
Look in alkaline igneous rocks country, the host setting where astrocyanite-(ce) typically forms. If you start seeing calcite, siderite, quartz in float, you are in the right ground. Field specimens usually show a platy crystals, rosettes habit, so 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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