Native selenium is a rare elemental mineral often found as needle-like crystals or powdery encrustations in hydrothermal deposits. It is known for its distinct metallic grey to reddish-grey appearance and is chemically sensitive, requiring careful storage to prevent degradation.
Is this selenium?
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 selenium with a known reference. Selenium 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. Selenium leaves a red streak.
- 3Read the lusterHold the specimen under a strong light. Selenium typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: gray, red.
- 5Look at form & habitCrystal system: trigonal. Typical habit: acicular crystals, encrustations, massive.
Often confused with
Selenium vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside selenium
Minerals reported to co-occur with selenium. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Se
- Mohs hardness
- 2
- Density
- 4.8 g/cm³
- Streak
- Red
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Acicular Crystals, Encrustations, Massive
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Industrial
- Host rock
- Hydrothermal Veins, Volcanic Fumaroles
- Typical price
- $50-500 depending on specimen quality and size
Where rockhounds find selenium
2 mapped spotsClassic worldwide localities
- Sierra de Cuchillo, Mexico
- Los Lamentos, Mexico
- Gladhammar, Sweden
- Taiyodo mine, Japan
Field-hunting tip
Look in hydrothermal veins, volcanic fumaroles country, the host setting where selenium typically forms. If you start seeing cinnabar, clausthalite, umannite in float, you are in the right ground. Field specimens usually show a acicular crystals, encrustations, massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah. Start trip planning there.
Common questions
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Find selenium on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
