Brezinaite is a very rare sulfide mineral originally discovered within the Brezina iron meteorite. It typically occurs as small, bronze-colored grains within the metallic matrix of meteorites, making it a highly prized specimen for meteorite collectors and planetary scientists.

Hardness

3.5-4.5

Mohs

Luster

Metallic to dull

Streak

Black

Transparency

Opaque

mineralrare

Brezinaite

Hardness: 3.5-4.5
Luster: Metallic to dull
Streak: Black
Transparency: Opaque

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Is this brezinaite?

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 brezinaite with a known reference. Brezinaite sits at Mohs 3.5-4.5, 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 to dull.
4
Match the color range
Compare against the expected color range: brownish gray, gray.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: granular.

Often confused with

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

mineral

Troilite

Mohs 3.5-4.5

How to tell apart: Streak differs, so Brezinaite leaves black, Troilite leaves dark grayish brown.

How to tell apart: Streak differs, so Brezinaite leaves black, Daubréelite leaves brown.

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Often found alongside brezinaite

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

All properties

Chemical formula: Cr₃S₄
Mohs hardness: 3.5-4.5
Density: 4.12 g/cm³
Colors: Brownish gray Gray
Streak: Black
Luster: Metallic to dull
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Granular
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific research
Host rock: In the metal matrix and contiguous to silicate inclusions (Tucson iron meteorite)

Where rockhounds find brezinaite

Classic worldwide localities

Tucson (type locality), New Baltimore, and Gibeon iron meteorites

Field-hunting tip

Where it forms: In the metal matrix and contiguous to silicate inclusions (Tucson iron meteorite). If you start seeing forsterite, enstatite, aluminous diopside in float, you are in the right ground. Typical habit: granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify brezinaite?+

Mohs hardness is 3.5-4.5. Luster: metallic to dull. The streak is black. Common colors include brownish gray, gray.

Where is brezinaite found?+

Notable localities include Tucson (type locality), New Baltimore, and Gibeon iron meteorites.

What rocks look like brezinaite?+

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

What minerals are found with brezinaite?+

Brezinaite commonly co-occurs with Forsterite, Enstatite, Aluminous diopside, Anorthite, Feldspathic glass, Kamacite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does brezinaite form in?+

Where it forms: In the metal matrix and contiguous to silicate inclusions (Tucson iron meteorite). Working float back to the host body is the standard way to chase a fresh occurrence.

What is brezinaite used for?+

Brezinaite is used in collector, scientific research.

Find brezinaite on the map

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