Peterandresenite is a rare manganese niobium oxide, typically orange. It was approved as a distinct mineral species in 2012. It was first described from AS Granit larvikite, Tvedalen, Larvik, Vestfold, Norway.

Hardness

2-2.5

Mohs

Luster

Vitreous to resinous

Streak

Pale orange

Transparency

Transparent to translucent

mineralrare

Peterandresenite

Hardness: 2-2.5
Luster: Vitreous to resinous
Streak: Pale orange
Transparency: Transparent to translucent

Is this peterandresenite?

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 peterandresenite with a known reference. Peterandresenite sits at Mohs 2-2.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: pale orange.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to resinous.
4
Match the color range
Compare against the expected color range: orange.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals.

Often confused with

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

mineral

Manganberzeliite

Mohs 4.5-5

How to tell apart: Manganberzeliite is the harder of the two (Mohs 4.5-5 vs. 2-2.5); streak differs, so Peterandresenite leaves pale orange, Manganberzeliite leaves white to yellow-orange; luster reads vitreous to resinous on Peterandresenite and resinous on Manganberzeliite.

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Often found alongside peterandresenite

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

All properties

Chemical formula: Mn₄Nb₆O₁₉(H₂O)₁₂·2H₂O
Mohs hardness: 2-2.5
Density: 3.10 g/cm³
Colors: Orange
Streak: Pale orange
Luster: Vitreous to resinous
Transparency: Transparent to translucent
Crystal system: Monoclinic
Crystal habit: Platy crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Formed at the hydrothermal stage on fracture surfaces and in tiny vugs in the center of a miaskitic pegmatite dike within the larvikites of a plutonic complex

Where rockhounds find peterandresenite

Classic worldwide localities

Granit larvikite (quarry level 4), Tvedalen, Larvik, Vestfold, Norway

Field-hunting tip

Where it forms: Formed at the hydrothermal stage on fracture surfaces and in tiny vugs in the center of a miaskitic pegmatite dike within the larvikites of a plutonic complex. If you start seeing analcime, fluorapophyllite-, arsenopyrite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify peterandresenite?+

Mohs hardness is 2-2.5. Luster: vitreous to resinous. The streak is pale orange. Common colors include orange.

Where is peterandresenite found?+

Notable localities include Granit larvikite (quarry level 4), Tvedalen, Larvik, Vestfold, Norway.

What rocks look like peterandresenite?+

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

What minerals are found with peterandresenite?+

Peterandresenite commonly co-occurs with Analcime, Fluorapophyllite-, Arsenopyrite, Behoite, Bertrandite, Calcite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does peterandresenite form in?+

Where it forms: Formed at the hydrothermal stage on fracture surfaces and in tiny vugs in the center of a miaskitic pegmatite dike within the larvikites of a plutonic complex. Working float back to the host body is the standard way to chase a fresh occurrence.

What is peterandresenite used for?+

Peterandresenite is used in collector.

Find peterandresenite on the map

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