Arsenopalladinite is an extremely rare palladium arsenide that typically occurs as small, metallic grains within mineralized zones. It is most often identified through micro-analysis in advanced collections due to its scarcity and similarity to other platinum-group minerals.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Arsenopalladinite

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

Is this arsenopalladinite?

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 arsenopalladinite with a known reference. Arsenopalladinite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Arsenopalladinite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Arsenopalladinite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, light yellow, gray.
5
Look at form & habit
Crystal system: triclinic. Typical habit: granular, anhedral masses.

Often confused with

Arsenopalladinite vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside arsenopalladinite

Minerals reported to co-occur with arsenopalladinite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Pd₈(As,Sb)₃
Mohs hardness: 3.5
Density: 9.94 g/cm³
Colors: White Light Yellow Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Triclinic
Crystal habit: Granular, Anhedral Masses
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Iron Formations
Typical price: $100-500 per micro-specimen

Where rockhounds find arsenopalladinite

Classic worldwide localities

Itabira, Minas Gerais, Brazil
Stillwater Complex, Montana, USA

Field-hunting tip

Look in hydrothermal veins in iron formations country — that is the host setting where arsenopalladinite typically forms. If you start seeing potarite, palladium, gold in float, you are in the right ground. Field specimens usually show a granular, anhedral masses habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify arsenopalladinite?+

Mohs hardness is 3.5. It typically shows a metallic luster. The streak is black. Common colors include white, light yellow, gray.

Where is arsenopalladinite found?+

Notable localities include Itabira, Minas Gerais, Brazil; Stillwater Complex, Montana, USA.

How much is arsenopalladinite worth?+

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

Is arsenopalladinite safe to handle?+

It contains toxic constituents. Contains arsenic, a toxic element. Handle with care, avoid inhaling dust, and wash hands thoroughly after handling. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like arsenopalladinite?+

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

What minerals are found with arsenopalladinite?+

Arsenopalladinite commonly co-occurs with Potarite, Palladium, Gold, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does arsenopalladinite form in?+

Arsenopalladinite typically forms in hydrothermal veins in iron formations. Working float back to the host body is the standard way to chase a fresh occurrence.

What is arsenopalladinite used for?+

Arsenopalladinite is used in collector.

Find arsenopalladinite on the map

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