Selenopolybasite is a rare selenium-dominant member of the polybasite group, typically found in low-temperature silver-rich hydrothermal veins. It usually appears as dark, metallic, pseudo-hexagonal tabular crystals that are difficult to distinguish visually from other members of the polybasite-pearceite series without laboratory analysis.
Is this selenopolybasite?
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 selenopolybasite with a known reference. Selenopolybasite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Selenopolybasite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Selenopolybasite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, iron-black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, massive, pseudo-hexagonal plates.
Often confused with
Selenopolybasite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside selenopolybasite
Minerals reported to co-occur with selenopolybasite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ag,Cu)₁₆(Sb,As)₂Se₉
- Mohs hardness
- 2.5-3
- Density
- 6.5-6.7 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Massive, Pseudo-hexagonal Plates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Epithermal Hydrothermal Veins
- Typical price
- $50-500 thumbnail depending on matrix and size
Where rockhounds find selenopolybasite
Classic worldwide localities
- Kremnitz, Slovakia
- Guanajuato, Mexico
- Freiberg, Germany
Field-hunting tip
Look in epithermal hydrothermal veins country, the host setting where selenopolybasite typically forms. If you start seeing acanthite, pyrargyrite, quartz in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, pseudo-hexagonal plates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify selenopolybasite?+
Where is selenopolybasite found?+
How much is selenopolybasite worth?+
Is selenopolybasite safe to handle?+
What rocks look like selenopolybasite?+
What minerals are found with selenopolybasite?+
What kind of rock does selenopolybasite form in?+
What is selenopolybasite used for?+
Find selenopolybasite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
