Spertiniite is a rare copper hydroxide mineral that typically occurs as small, delicate blue to blue-green platy crystals. It is primarily found as a late-stage secondary mineral in cavities of alkaline igneous rocks, most notably at the Mont Saint-Hilaire locality in Canada.
Is this spertiniite?
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 spertiniite with a known reference. Spertiniite 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. Spertiniite leaves a pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Spertiniite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, crusts.
Often confused with
Spertiniite 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 Spertiniite leaves pale blue, Azurite leaves light blue; luster reads vitreous on Spertiniite and vitreous to dull on Azurite.
How to tell apart: Malachite is the harder of the two (Mohs 3.5-4 vs. 2); streak differs, so Spertiniite leaves pale blue, Malachite leaves light green.
Often found alongside spertiniite
Minerals reported to co-occur with spertiniite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu(OH)₂
- Mohs hardness
- 2
- Density
- 2.9 g/cm³
- Colors
- Streak
- Pale Blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Crusts
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Complexes
- Typical price
- $50-300+ for micro-mounts and thumbnail specimens
Where rockhounds find spertiniite
Classic worldwide localities
- Poudrette quarry, Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Look in alkaline igneous complexes country, the host setting where spertiniite typically forms. If you start seeing dawsonite, analcime, calcite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find spertiniite on the map
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