Gupeiite is an extremely rare iron silicide mineral first discovered in the Luobusa ophiolite of Tibet. It typically appears as small metallic grains and is found primarily in ultramafic rocks associated with high-pressure, mantle-derived environments.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Gupeiite

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

Is this gupeiite?

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 gupeiite with a known reference. Gupeiite 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: steel gray, black.
5
Look at form & habit
Crystal system: cubic. Typical habit: anhedral grains, irregular masses.

Often confused with

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

Often found alongside gupeiite

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

All properties

Chemical formula: Fe₃Si
Mohs hardness: 5
Density: 7.15 g/cm³
Colors: Steel gray Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral grains, irregular masses
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific research
Host rock: Innermost in spheres, surrounded by nickel-iron minerals and their oxidation products, apparently of extraterrestrial origin, found in placers

Where rockhounds find gupeiite

Classic worldwide localities

Yanshan Mountains, Hebei Province, China

Field-hunting tip

Where it forms: Innermost in spheres, surrounded by nickel-iron minerals and their oxidation products, apparently of extraterrestrial origin, found in placers. If you start seeing xifengite, kamacite, taenite in float, you are in the right ground. Typical habit: anhedral grains, irregular masses. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gupeiite?+

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

Where is gupeiite found?+

Notable localities include Yanshan Mountains, Hebei Province, China.

What rocks look like gupeiite?+

Gupeiite is most often confused with Xifengite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with gupeiite?+

Gupeiite commonly co-occurs with Xifengite, Kamacite, Taenite, Magnetite, Wüstite, Maghemite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gupeiite form in?+

Where it forms: Innermost in spheres, surrounded by nickel-iron minerals and their oxidation products, apparently of extraterrestrial origin, found in placers. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gupeiite used for?+

Gupeiite is used in collector, scientific research.

Find gupeiite on the map

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