Joanneumite is a rare copper-organic mineral first discovered in the Rowley Mine of Arizona. It typically forms as small, distinctive blue tabular crystals or crusts within oxidized copper zones. Because it contains nitrogen-bearing organic ligands, it is of significant interest to mineralogists studying exotic mineral species.
Is this joanneumite?
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 joanneumite with a known reference. Joanneumite 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. Joanneumite leaves a pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Joanneumite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, greenish-blue.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals, crusts.
Often confused with
Joanneumite 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 — Joanneumite leaves pale blue, Azurite leaves light blue; luster reads vitreous on Joanneumite and vitreous to dull on Azurite.
How to tell apart: Streak differs — Joanneumite leaves pale blue, Chalcanthite leaves white.
Often found alongside joanneumite
Minerals reported to co-occur with joanneumite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu(C₃H₄N₂)₂Cl₂
- Mohs hardness
- 2
- Density
- 2.47 g/cm³
- Colors
- Streak
- Pale Blue
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Tabular Crystals, Crusts
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Copper Ore Deposits
- Typical price
- $100-500 for small high-quality micromounts
Where rockhounds find joanneumite
Classic worldwide localities
- Rowley Mine, Arizona, USA
Field-hunting tip
Look in oxidized copper ore deposits country — that is the host setting where joanneumite typically forms. If you start seeing azurite, malachite, atacamite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find joanneumite on the map
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