Atheneite is a very rare palladium arsenide mineral typically found as microscopic grains within platinum-group element deposits. It is best identified through microscopic examination and chemical analysis due to its extremely small, unassuming appearance in polished sections.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Atheneite

Hardness: 5
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this atheneite?

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 atheneite with a known reference. Atheneite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: black.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: gray white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: anhedral grains and inclusions.

Often confused with

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

mineral

Potarite

Mohs 3.5

How to tell apart: Atheneite is noticeably harder (Mohs 5 vs. 3.5); streak differs, so Atheneite leaves black, Potarite leaves silver-white.

How to tell apart: Streak differs, so Atheneite leaves black, Palladium leaves silver-white.

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Often found alongside atheneite

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

All properties

Chemical formula: (Pd,Hg)₃As
Mohs hardness: 5
Density: 10.2 g/cm³
Colors: Gray white
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Anhedral grains and inclusions
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In concentrates from gold washings

Where rockhounds find atheneite

Classic worldwide localities

Itabira (type locality), and in the Cauê and Conceição iron mines, Minas Gerais, and in the Serra Pelada Au–Pd–Pt deposit, Pará, Brazil
Merensky Reef, Bushveldt complex, Transvaal, South Africa
Found around Zlatoust, Ural Mountains, Russia

Field-hunting tip

Where it forms: In concentrates from gold washings. If you start seeing arsenopalladinite, palladseite, isomertieite in float, you are in the right ground. Typical habit: anhedral grains and inclusions. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify atheneite?+

Mohs hardness is 5. Luster: metallic. The streak is black. Common colors include gray white.

Where is atheneite found?+

Notable localities include Itabira (type locality), and in the Cauê and Conceição iron mines, Minas Gerais, and in the Serra Pelada Au–Pd–Pt deposit, Pará, Brazil; Merensky Reef, Bushveldt complex, Transvaal, South Africa; Found around Zlatoust, Ural Mountains, Russia.

Is atheneite safe to handle?+

Atheneite contains arsenic and mercury and calls for real care. Contains arsenic and mercury; avoid inhalation of dust and handle with caution to prevent ingestion.

What rocks look like atheneite?+

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

What minerals are found with atheneite?+

Atheneite commonly co-occurs with Arsenopalladinite, Palladseite, Isomertieite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does atheneite form in?+

Where it forms: In concentrates from gold washings. Working float back to the host body is the standard way to chase a fresh occurrence.

What is atheneite used for?+

Atheneite is used in collector.

Find atheneite on the map

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