Alburnite is a rare silver germanium sulfotelluride found in low-temperature hydrothermal epithermal deposits. It typically occurs as small, metallic black anhedral grains associated with other sulfide and telluride minerals.

Hardness

Mohs

Luster

Metallic

Transparency

Opaque

mineralrareArgyrodite Group family

Alburnite

Hardness: 4
Luster: Metallic
Transparency: Opaque

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Is this alburnite?

4-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 alburnite with a known reference. Alburnite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
2
Read the luster
Hold the specimen under a strong light. Luster: metallic.
3
Match the color range
Compare against the expected color range: black, dark gray.
4
Look at form & habit
Crystal system: cubic. Typical habit: anhedral grains.

Often confused with

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

mineral

Argyrodite

Mohs 2.5-3

How to tell apart: Alburnite is noticeably harder (Mohs 4 vs. 2.5-3); luster reads metallic on Alburnite and strong metallic on Argyrodite.

How to tell apart: Alburnite is noticeably harder (Mohs 4 vs. 2.5).

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Often found alongside alburnite

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

All properties

Chemical formula: Ag₈GeTe₂S₄
Mohs hardness: 4
Density: 7.828 g/cm³
Colors: Black Dark gray
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In an epithermal hydrothermal Au-Ag vein

Where rockhounds find alburnite

Classic worldwide localities

Cârnicel vein, Roşia Montana Au-Ag deposit, Apuseni Mountains, Romania

Field-hunting tip

Where it forms: In an epithermal hydrothermal Au-Ag vein. If you start seeing tetrahedrite, galena, pyrite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify alburnite?+

Mohs hardness is 4. Luster: metallic. Common colors include black, dark gray.

Where is alburnite found?+

Notable localities include Cârnicel vein, Roşia Montana Au-Ag deposit, Apuseni Mountains, Romania.

Is alburnite safe to handle?+

Contains silver, germanium, tellurium, and sulfur. Wash hands thoroughly after handling and avoid inhalation of dust.

What rocks look like alburnite?+

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

What minerals are found with alburnite?+

Alburnite commonly co-occurs with Tetrahedrite, Galena, Pyrite, Sphalerite, Chalcopyrite, Hessite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does alburnite form in?+

Where it forms: In an epithermal hydrothermal Au-Ag vein. Working float back to the host body is the standard way to chase a fresh occurrence.

What is alburnite used for?+

Alburnite is used in collector.

Find alburnite on the map

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