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, 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.