Bleasdaleite is a rare copper phosphate mineral known primarily from its type locality in the Carrock Mine of the English Lake District. It typically appears as thin, blue to blue-green platy crystals or as secondary crusts in weathered hydrothermal veins. Collectors prize it for its rarity and its association with other rare secondary copper minerals.
Is this bleasdaleite?
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 bleasdaleite with a known reference. Bleasdaleite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bleasdaleite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Bleasdaleite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts, aggregates.
Often confused with
Bleasdaleite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Paranatisite is the harder of the two (Mohs 5 vs. 3-4).
How to tell apart: Turquoise is the harder of the two (Mohs 5-6 vs. 3-4); luster reads vitreous on Bleasdaleite and waxy on Turquoise.
How to tell apart: Streak differs — Bleasdaleite leaves white, Pseudomalachite leaves light green.
Often found alongside bleasdaleite
Minerals reported to co-occur with bleasdaleite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₂Cu₅(PO₄)₄Cl·5H₂O
- Mohs hardness
- 3-4
- Density
- 3.5 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Crusts, Aggregates
- Cleavage
- None Observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Greisenized Granite
- Typical price
- $50-300 per specimen
Where rockhounds find bleasdaleite
Classic worldwide localities
- Carrock Mine, Cumbria, England
Field-hunting tip
Look in hydrothermal veins in greisenized granite country — that is the host setting where bleasdaleite typically forms. If you start seeing chalcopyrite, arsenopyrite, liroconite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find bleasdaleite on the map
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