Russoite is a rare ammonium-bearing arsenic-antimony oxide mineral typically found in volcanic fumaroles. It forms distinct yellow, platy, or tabular crystals associated with other arsenic-rich minerals in high-temperature volcanic settings.
Is this russoite?
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 russoite with a known reference. Russoite sits at Mohs 1.5-2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Russoite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Russoite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts.
Often confused with
Russoite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Russoite leaves yellow, Arsenolite leaves white; luster reads adamantine on Russoite and vitreous on Arsenolite.
How to tell apart: Streak differs — Russoite leaves yellow, Senarmontite leaves white.
Often found alongside russoite
Minerals reported to co-occur with russoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NH₄Cl(As,Sb)₄O₆
- Mohs hardness
- 1.5-2
- Density
- 3.84 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Crusts
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Fumarolic Deposits
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find russoite
Classic worldwide localities
- La Fossa crater, Vulcano, Aeolian Islands, Italy
Field-hunting tip
Look in fumarolic deposits country — that is the host setting where russoite typically forms. If you start seeing arsenolite, senarmontite, realgar in float, you are in the right ground. Field specimens usually show a platy crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find russoite on the map
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