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. Streak: orange-yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: dark crimson red, dark orange, brown, lemon yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, reniform, tabular.
Often confused with
Xanthoconite vs. its common look-alikes, and how to tell them apart in the field.
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
- 5.54 g/cm³
- Colors
- Streak
- Orange-yellow
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, reniform, tabular
- Cleavage
- Distinct on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Typically associated with other silver sulfosalts in hydrothermal veins
Where rockhounds find xanthoconite
Classic worldwide localities
- General Petite mine, Atlanta district, Elmore Co., Idaho, and from about 13 km north of Niarada, in the Flathead mine, Flathead Co., Montana, USA
- Jáchymov (Joachimsthal), Příbram, and Třebsko, Czech Republic
- Saxony, Germany, at Freiberg, Annaberg, Marienberg, Johanngeorgenstadt, and Schneeberg
- St. Andreasberg, in the Harz Mountains
- Baia Sprie (Felsőbánya), Romania
- Sainte-Marie-aux-Mines, Haut-Rhin, France
Field-hunting tip
Where it forms: Typically associated with other silver sulfosalts in hydrothermal veins. If you start seeing proustite, pyrargyrite, acanthite in float, you are in the right ground. Typical habit: massive, reniform, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify xanthoconite?+
Where is xanthoconite found?+
Is xanthoconite safe to handle?+
What rocks look like xanthoconite?+
What minerals are found with xanthoconite?+
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Find xanthoconite on the map
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