Wüstite is a rare iron oxide mineral that is typically found in terrestrial basaltic environments or as meteoritic inclusions. It is notable for being unstable at standard surface temperatures and pressures, often altering quickly to magnetite or hematite.

Hardness

5-5.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Wüstite

Also: FeO

Hardness: 5-5.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this wüstite?

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 wüstite with a known reference. Wüstite sits at Mohs 5-5.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Wüstite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Wüstite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black, dark gray.
5
Look at form & habit
Crystal system: cubic. Typical habit: massive, granular, or as inclusions.

Often confused with

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

How to tell apart: Streak differs — Wüstite leaves black, Iron Ore leaves reddish-brown to black; luster reads metallic on Wüstite and metallic to submetallic on Iron Ore.

Compare →

Often found alongside wüstite

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

All properties

Chemical formula: FeO
Mohs hardness: 5-5.5
Density: 5.7-5.9 g/cm³
Colors: Black Dark Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Massive, Granular, Or as Inclusions
Cleavage: None
Rarity: Rare
Uses: Scientific Research, Collector
Host rock: Basaltic Rocks, Meteorites, And High-temperature Furnace Products
Typical price: $20-150 for small specimens

Where rockhounds find wüstite

Classic worldwide localities

Disko Island, Greenland
Kola Peninsula, Russia
Bühl, Germany

Field-hunting tip

Look in basaltic rocks, meteorites, and high-temperature furnace products country — that is the host setting where wüstite typically forms. If you start seeing magnetite, iron, troilite in float, you are in the right ground. Field specimens usually show a massive, granular, or as inclusions habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify wüstite?+

Mohs hardness is 5-5.5. It typically shows a metallic luster. The streak is black. Common colors include black, dark gray.

Where is wüstite found?+

Notable localities include Disko Island, Greenland; Kola Peninsula, Russia; Bühl, Germany.

How much is wüstite worth?+

Typical asking prices fall in the range of $20-150 for small specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like wüstite?+

Wüstite is most often confused with Magnetite, Iron Ore. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with wüstite?+

Wüstite commonly co-occurs with Magnetite, Iron, Troilite, Wustite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does wüstite form in?+

Wüstite typically forms in basaltic rocks, meteorites, and high-temperature furnace products. Working float back to the host body is the standard way to chase a fresh occurrence.

What is wüstite used for?+

Wüstite is used in scientific research, collector.

Find wüstite on the map

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