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.
Is this wüstite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch wüstite with a known reference. Wüstite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: gray.
- 5Look at form & habitCrystal 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.
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
- Density
- 5.88 g/cm³
- Colors
- 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
- Formed as an alteration product of other iron-bearing minerals at high temperatures in a highly reducing environment; in highly-reduced iron-bearing basalts; as inclusions in diamonds in kimberlites
Where rockhounds find wüstite
Classic worldwide localities
- Scharnhausen, near Stuttgart, Baden-Württemberg, and at Bühl, near Weimar, Hesse, Germany
- Disko Island, near Uivfaq and Kitdlı̂t, Greenland
- Pathardih colliery, Jharia coalfield, Bihar, India
Field-hunting tip
Where it forms: Formed as an alteration product of other iron-bearing minerals at high temperatures in a highly reducing environment; in highly-reduced iron-bearing basalts; as inclusions in diamonds in kimberlites. If you start seeing iron, hematite, magnetite in float, you are in the right ground. Typical habit: massive, granular, or as inclusions. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify wüstite?+
Where is wüstite found?+
What rocks look like wüstite?+
What minerals are found with wüstite?+
What kind of rock does wüstite form in?+
What is wüstite used for?+
Find wüstite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
