Arsenudinaite is an extremely rare palladium arsenide mineral typically found in high-temperature volcanic fumarole environments. It usually occurs as microscopic grains or small aggregates and is primarily identified through advanced analytical techniques due to its extreme scarcity.

Hardness

3.5-4

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Arsenudinaite

Hardness: 3.5-4
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this arsenudinaite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try 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.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Arsenudinaite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Arsenudinaite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: silver-white, pale gray.
5
Look at form & habit
Crystal system: orthorhombic. 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: Sperrylite is the harder of the two (Mohs 6-7 vs. 3.5-4).

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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: As₂Pd₃
Mohs hardness: 3.5-4
Density: 6.8-7.2 g/cm³
Colors: Silver-white Pale Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Tabular Crystals, Massive, Granular
Cleavage: Distinct in One Direction
Rarity: Rare
Uses: Collector
Host rock: Fumarolic Volcanic Deposits
Typical price: $100-500 for small micro-mounts

Where rockhounds find arsenudinaite

Classic worldwide localities

Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia

Field-hunting tip

Look in fumarolic volcanic deposits country — that is 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

How do you identify arsenudinaite?+

Mohs hardness is 3.5-4. It typically shows a metallic luster. The streak is black. Common colors include silver-white, pale gray.

Where is arsenudinaite found?+

Notable localities include Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia.

How much is arsenudinaite worth?+

Typical asking prices fall in the range of $100-500 for small micro-mounts. Quality, size, and provenance can move individual specimens well outside that range.

Is arsenudinaite safe to handle?+

It contains toxic constituents. Contains arsenic, which is toxic; always wash hands after handling and avoid inhaling dust or powder. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like arsenudinaite?+

Arsenudinaite is most often confused with Palladseite, Sperrylite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with arsenudinaite?+

Arsenudinaite commonly co-occurs with sopcheite, temagamite, palladseite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does arsenudinaite form in?+

Arsenudinaite typically forms in fumarolic volcanic deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is arsenudinaite used for?+

Arsenudinaite is used in collector.

Find arsenudinaite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.