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.

Hardness
2.5
Mohs
Luster
Metallic
Streak
Black
Transparency
Opaque

Is this billingsleyite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

  • 1
    Test the hardness
    Try to scratch billingsleyite with a known reference. Billingsleyite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Billingsleyite leaves a black streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Billingsleyite typically shows a metallic luster.
  • 4
    Match the color range
    Compare against the expected color range: silver-white, gray.
  • 5
    Look at form & habit
    Crystal system: monoclinic. 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
6.9 g/cm³
Streak
Black
Luster
Metallic
Transparency
Opaque
Crystal system
Monoclinic
Crystal habit
Massive, Granular, Or Fine-grained Aggregates
Cleavage
None
Rarity
Rare
Uses
Collector
Host rock
Hydrothermal Silver-lead Veins
Typical price
$50-500 thumbnail, depending on quality

Where rockhounds find billingsleyite

Classic worldwide localities

  • Hilltop mine, San Bernardino County, California, USA

Field-hunting tip

Look in hydrothermal silver-lead veins country — that is the host setting where billingsleyite typically forms. If you start seeing arsenopyrite, galena, sphalerite in float, you are in the right ground. Field specimens usually show a massive, granular, or fine-grained aggregates habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify billingsleyite?+
Mohs hardness is 2.5. It typically shows a metallic luster. The streak is black. Common colors include silver-white, gray.
Where is billingsleyite found?+
Notable localities include Hilltop mine, San Bernardino County, California, USA.
How much is billingsleyite worth?+
Typical asking prices fall in the range of $50-500 thumbnail, depending on quality. Quality, size, and provenance can move individual specimens well outside that range.
Is billingsleyite safe to handle?+
It contains toxic constituents. Contains arsenic and silver; wash hands thoroughly after handling and avoid inhaling dust. Wear proper personal protective equipment during cleaning or trimming specimens. Handle with care, avoid grinding or breathing dust, and store separately.
What rocks look like billingsleyite?+
Billingsleyite is most often confused with Acanthite, Pearceite, Polybasite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with billingsleyite?+
Billingsleyite commonly co-occurs with Arsenopyrite, Galena, Sphalerite, Calcite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does billingsleyite form in?+
Billingsleyite typically forms in hydrothermal silver-lead veins. Working float back to the host body is the standard way to chase a fresh occurrence.
What is billingsleyite used for?+
Billingsleyite is used in collector.

Find billingsleyite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.

Download on the App StoreGet it on Google Play