Mambertiite is a rare bismuth molybdenum hydroxide, typically pale yellow. It is a secondary oxidation product. It was first described from Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy.

Hardness

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Mambertiite

Mambertiite is a rare bismuth molybdenum hydroxide, typically pale yellow. It is a secondary oxidation product. It was first described from Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy.

Hardness: 2
Luster: Adamantine
Streak: White
Transparency: Transparent

No image

Is this mambertiite?

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 mambertiite with a known reference. Mambertiite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: pale yellow.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular crystals.

Often confused with

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

mineral

Bismutite

Mohs 2.5-3.5

How to tell apart: Streak differs, so Mambertiite leaves white, Bismutite leaves gray; luster reads adamantine on Mambertiite and vitreous, waxy, may be dull to earthy on Bismutite.

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Often found alongside mambertiite

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

All properties

Chemical formula: BiMo⁵⁺₂.₈O₈(OH)
Mohs hardness: 2
Density: 5.720 g/cm³
Colors: Pale yellow
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Triclinic
Crystal habit: Tabular crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: A secondary oxidation product

Where rockhounds find mambertiite

Classic worldwide localities

Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy

Field-hunting tip

Where it forms: A secondary oxidation product. If you start seeing ferrimolybdite, muscovite, sardignaite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mambertiite?+

Mohs hardness is 2. Luster: adamantine. The streak is white. Common colors include pale yellow.

Where is mambertiite found?+

Notable localities include Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy.

Is mambertiite safe to handle?+

Contains bismuth, which is toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust.

What rocks look like mambertiite?+

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

What minerals are found with mambertiite?+

Mambertiite commonly co-occurs with Ferrimolybdite, Muscovite, Sardignaite, Wulfenite, Quartz, Molybdenite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mambertiite form in?+

Where it forms: A secondary oxidation product. Working float back to the host body is the standard way to chase a fresh occurrence.

What is mambertiite used for?+

Mambertiite is used in collector.

Find mambertiite on the map

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