Billingsleyite is a rare silver arsenic sulfide mineral that typically occurs as small, metallic grains within hydrothermal ore deposits. It is best identified through laboratory methods like X-ray diffraction or microprobe analysis because it is visually similar to several other complex silver sulfosalts. It is primarily sought after by advanced collectors of rare minerals and silver species.
Is this billingsleyite?
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 billingsleyite with a known reference. Billingsleyite sits at Mohs 2.5, 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: lead gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: massive, granular, or fine-grained aggregates.
Often confused with
Billingsleyite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside billingsleyite
Minerals reported to co-occur with billingsleyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₇AsS₆
- Mohs hardness
- 2.5
- Density
- 5.92 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Massive, granular, or fine-grained aggregates
- Cleavage
- Indistinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Believed to have occurred in a body of high-grade hydrothermal silver ore
Where rockhounds find billingsleyite
Classic worldwide localities
- North Lily mine, East Tintic district, Utah Co., Utah, USA
Field-hunting tip
Where it forms: Believed to have occurred in a body of high-grade hydrothermal silver ore. If you start seeing acanthite, tennantite, bismuthinite in float, you are in the right ground. Typical habit: massive, granular, or fine-grained aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
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Find billingsleyite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
