Xanthoconite is a rare silver arsenic sulfide that typically forms as bright orange to reddish-brown tabular crystals. It is a dimorph of proustite and is almost exclusively found in high-grade silver deposits associated with other silver-bearing minerals.
Is this xanthoconite?
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 xanthoconite with a known reference. Xanthoconite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Xanthoconite leaves a orange to yellow streak.
- 3Read the lusterHold the specimen under a strong light. Xanthoconite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: orange, red, yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular, prismatic crystals, sometimes as crusts.
Often confused with
Xanthoconite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Xanthoconite leaves orange to yellow, Proustite leaves scarlet.
How to tell apart: Streak differs — Xanthoconite leaves orange to yellow, Pyrargyrite leaves red; luster reads adamantine on Xanthoconite and metallic to adamantine on Pyrargyrite.
Often found alongside xanthoconite
Minerals reported to co-occur with xanthoconite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₃AsS₃
- Mohs hardness
- 2-3
- Density
- 5.5 g/cm³
- Streak
- Orange to Yellow
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular, Prismatic Crystals, Sometimes as Crusts
- Cleavage
- Distinct On {101}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Silver Veins
- Typical price
- $50-500 depending on crystal size and quality
Where rockhounds find xanthoconite
Classic worldwide localities
- Freiberg, Saxony, Germany
- Jáchymov, Czech Republic
- Chañarcillo, Chile
- Bou Azzer, Morocco
Field-hunting tip
Look in hydrothermal silver veins country — that is the host setting where xanthoconite typically forms. If you start seeing proustite, pyrargyrite, stephanite in float, you are in the right ground. Field specimens usually show a tabular, prismatic crystals, sometimes as crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find xanthoconite on the map
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