Arsenudinaite is a rare sodium magnesium arsenate, typically beige or brownish-yellowish. It is a sublimate at an active volcanic fumarole. It was first described from the Arsenatnaya fumarole, Kamchatka peninsula, Far-Eastern Region, Russia.
Is this arsenudinaite?
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 arsenudinaite with a known reference. Arsenudinaite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Arsenudinaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Arsenudinaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: beige, brownish-yellowish, colorless.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: tabular crystals, massive, granular.
Often confused with
Arsenudinaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Arsenudinaite leaves white, Palladseite leaves black; luster reads vitreous on Arsenudinaite and metallic on Palladseite.
How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 3.5-4); streak differs, so Arsenudinaite leaves white, Sperrylite leaves black; luster reads vitreous on Arsenudinaite and metallic on Sperrylite.
Often found alongside arsenudinaite
Minerals reported to co-occur with arsenudinaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaMg₄(AsO₄)₃
- Mohs hardness
- 3.5-4
- Density
- 3.816 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Tabular Crystals, Massive, Granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Fumarolic Volcanic Deposits
Where rockhounds find arsenudinaite
Classic worldwide localities
- Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia
Field-hunting tip
Look in fumarolic volcanic deposits country, the host setting where arsenudinaite typically forms. If you start seeing sopcheite, temagamite, palladseite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find arsenudinaite on the map
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