Umangite is a rare copper selenide mineral typically found as massive, granular aggregates with a striking bluish black to dull iridescent purple color. It is almost exclusively identified by its metallic luster and association with other rare selenium-bearing minerals in hydrothermal vein deposits.
Is this umangite?
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 umangite with a known reference. Umangite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: blue black, brownish black, red violet.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: massive.
Often confused with
Umangite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside umangite
Minerals reported to co-occur with umangite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃Se₂
- Mohs hardness
- 3
- Density
- 6.44-6.49 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Massive
- Cleavage
- Poor, rectangular
- Rarity
- Uncommon
- Uses
- Collector, Ore of copper
- Host rock
- With other selenides in hydrothermal veins, formed below 112°C
Where rockhounds find umangite
Classic worldwide localities
- Sierra de Umango (type locality), in the Santa Brigida mine, at Los Llantenes, and from Tuminico, Sierra de Cacho, La Rioja Province, Argentina
- Cerro de Cacheuta, Mendoza Province, Argentina
- Lodge Bay on Lake Athabasca, to Ato Bay on Beaverlodge Lake, Saskatchewan, and on Christopher Island, Baker Lake, Northwest Territories, Canada
- Skrikerum, near Tryserum, Kalmar, Sweden
- Harz Mountains, at St. Andreasberg, Tilkerode, Zorge, Lerbach, and Clausthal, Germany
- Chaméane uranium mine, near Vernet-la-Varenne, Puy-de-Dôme, France
Field-hunting tip
Where it forms: With other selenides in hydrothermal veins, formed below 112°C. If you start seeing clausthalite, tiemannite, berzelianite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find umangite on the map
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