Cadmoselite is an extremely rare cadmium selenide mineral that typically occurs as microscopic black grains or inclusions within larger ore minerals. It is primarily found in complex hydrothermal settings alongside other selenides and uranium minerals. Due to its scarcity and metallic appearance, it is highly sought after by advanced mineral collectors specializing in rare species.
Is this cadmoselite?
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 cadmoselite with a known reference. Cadmoselite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Cadmoselite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Cadmoselite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, dark gray.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: fine-grained massive or as minute inclusions.
Often confused with
Cadmoselite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Cadmoselite leaves black, Greenockite leaves brick-red to orange-yellow; luster reads metallic on Cadmoselite and adamantine to resinous on Greenockite.
How to tell apart: Streak differs — Cadmoselite leaves black, Sphalerite leaves white to yellow-brown; luster reads metallic on Cadmoselite and resinous to submetallic on Sphalerite.
Often found alongside cadmoselite
Minerals reported to co-occur with cadmoselite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CdSe
- Mohs hardness
- 3.5-4
- Density
- 5.68 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Fine-grained Massive or as Minute Inclusions
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Epithermal Deposits and Uranium-bearing Hydrothermal Veins
- Typical price
- $50-300 per micro-mount or small specimen
Where rockhounds find cadmoselite
Classic worldwide localities
- Kazakhstan
- Czech Republic
- USA
Field-hunting tip
Look in epithermal deposits and uranium-bearing hydrothermal veins country — that is the host setting where cadmoselite typically forms. If you start seeing clausthalite, uraninite, sphalerite in float, you are in the right ground. Field specimens usually show a fine-grained massive or as minute inclusions habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cadmoselite?+
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How much is cadmoselite worth?+
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What rocks look like cadmoselite?+
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Find cadmoselite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
