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, so 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, so 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, 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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