Xanthiosite is a rare nickel arsenate mineral typically found as secondary crusts or delicate acicular aggregates in oxidized hydrothermal nickel-arsenic veins. It is distinguished by its bright, characteristic yellow color, though it is often confused with other secondary nickel minerals that form in similar oxidation zones.
Is this xanthiosite?
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 xanthiosite with a known reference. Xanthiosite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Xanthiosite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Xanthiosite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: yellow, orange-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crusts, acicular aggregates.
Often confused with
Xanthiosite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Xanthiosite is noticeably harder (Mohs 3.5 vs. 1.5-2.5); streak differs — Xanthiosite leaves yellow, Annabergite leaves pale green; luster reads resinous on Xanthiosite and pearly, vitreous on Annabergite.
How to tell apart: Xanthiosite is noticeably harder (Mohs 3.5 vs. 2-2.5); streak differs — Xanthiosite leaves yellow, Morenosite leaves white; luster reads resinous on Xanthiosite and vitreous on Morenosite.
Often found alongside xanthiosite
Minerals reported to co-occur with xanthiosite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₃(AsO₄)₂
- Mohs hardness
- 3.5
- Density
- 4.15 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Crusts, Acicular Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find xanthiosite
Classic worldwide localities
- Johanngeorgenstadt, Germany
- Schneeberg, Germany
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where xanthiosite typically forms. If you start seeing annabergite, nickeline, arsenopyrite in float, you are in the right ground. Field specimens usually show a crusts, acicular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find xanthiosite on the map
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