Native selenium is a rare element that typically occurs as soft, metallic-looking crystals or as reddish crusts around volcanic vents. It is frequently associated with selenium sulfides and sulfoselenides, and collectors should handle it with caution due to the inherent toxicity of selenium compounds.
Is this native 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 native selenium with a known reference. Native 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. Streak: red.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: gray, purple gray, reddish.
- 5Look at form & habitCrystal system: trigonal. Typical habit: crystalline, disseminated, granular.
Often confused with
Native Selenium vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Native Selenium leaves red, Cinnabar leaves scarlet; luster reads metallic on Native Selenium and adamantine, inclining to metallic when dark; dull in friable material on Cinnabar.
How to tell apart: Streak differs, so Native Selenium leaves red, Realgar leaves red-orange to red; luster reads metallic on Native Selenium and resinous to greasy on Realgar.
Often found alongside native selenium
Minerals reported to co-occur with native 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
- 4.80 g/cm³
- Streak
- Red
- Luster
- Metallic
- Transparency
- Opaque, transparent in very thin fragments
- Crystal system
- Trigonal
- Crystal habit
- Crystalline, disseminated, granular
- Cleavage
- Good on {0112}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed at relatively low temperatures by sublimation of fumarolic vapors, and from oxidation of selenium-bearing organic compounds in sandstone U–V deposits; from burning coal and pyritic ores
Where rockhounds find native selenium
Classic worldwide localities
- United Verde mine, Jerome, Yavapai Co., Arizona, USA
- Colorado Plateau, as in the Peanut mine, Bull Canyon, Uravan district, Montrose Co., Colorado, and the Parco No. 23 mine, Thompsons district, Grand Co., Utah, USA
- Road Hog No. 1A mine, Black Hills, Fall River Co., South Dakota, USA
- Mopung Hills, Churchill Co., and the Gold Quarry mine, near Carlin, Eureka Co., Nevada, USA
- Moctezuma (Bambolla) mine, 12 km south of Moctezuma, Sonora, Mexico
- Pacajake mine, Hiaco, 24 km east-northeast of Colquechaca, Potosí, Bolivia
Field-hunting tip
Where it forms: Formed at relatively low temperatures by sublimation of fumarolic vapors, and from oxidation of selenium-bearing organic compounds in sandstone U–V deposits; from burning coal and pyritic ores. If you start seeing pyrite, ferroselite, zippeite in float, you are in the right ground. Typical habit: crystalline, disseminated, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify native selenium?+
Where is native selenium found?+
Is native selenium safe to handle?+
What rocks look like native selenium?+
What minerals are found with native selenium?+
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Find native selenium on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
