Landesite is a very rare secondary phosphate mineral found primarily in complex granite pegmatites. It typically forms as a weathering product of manganese-rich phosphates, often appearing as yellowish-brown platy crystals or as micaceous crusts.

Hardness

3-3.5

Mohs

Luster

Vitreous

Streak

Light brown

Transparency

Translucent

mineralrareRedmondite Group family

Landesite

Hardness: 3-3.5
Luster: Vitreous
Streak: Light brown
Transparency: Translucent

Is this landesite?

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 landesite with a known reference. Landesite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: light brown.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: brown.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: platy or micaceous aggregates.

Often confused with

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

mineral

Fairfieldite

Mohs 3.5

How to tell apart: Streak differs, so Landesite leaves light brown, Fairfieldite leaves white; luster reads vitreous on Landesite and pearly to subadamantine, vitreous on the {001} cleavage on Fairfieldite.

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Often found alongside landesite

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

All properties

Chemical formula: Mn₉Fe₃(PO₄)₈(OH)₃(H₂O)₉
Mohs hardness: 3-3.5
Density: 3.026 g/cm³
Colors: Brown
Streak: Light brown
Luster: Vitreous
Transparency: Translucent
Crystal system: Orthorhombic
Crystal habit: Platy or micaceous aggregates
Cleavage: Good on {100}; poor ⊥ {100}
Rarity: Rare
Uses: Collector
Host rock: Replacing reddingite in a complex granite pegmatite (Berry quarry, Maine, USA)

Where rockhounds find landesite

Classic worldwide localities

Berry quarry, Poland, Androscoggin Co., and the Emmons quarry, Greenwood, Oxford Co., Maine, USA
Branchville, Fairfield Co., Connecticut, USA
Hagendorf, Bavaria, Germany

Field-hunting tip

Where it forms: Replacing reddingite in a complex granite pegmatite (Berry quarry, Maine, USA). If you start seeing reddingite, lithiophilite, rhodochrosite in float, you are in the right ground. Typical habit: platy or micaceous aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify landesite?+

Mohs hardness is 3-3.5. Luster: vitreous. The streak is light brown. Common colors include brown.

Where is landesite found?+

Notable localities include Berry quarry, Poland, Androscoggin Co., and the Emmons quarry, Greenwood, Oxford Co., Maine, USA; Branchville, Fairfield Co., Connecticut, USA; Hagendorf, Bavaria, Germany.

What rocks look like landesite?+

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

What minerals are found with landesite?+

Landesite commonly co-occurs with Reddingite, Lithiophilite, Rhodochrosite, Eosphorite, Fairfieldite, Apatite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does landesite form in?+

Where it forms: Replacing reddingite in a complex granite pegmatite (Berry quarry, Maine, USA). Working float back to the host body is the standard way to chase a fresh occurrence.

What is landesite used for?+

Landesite is used in collector.

Find landesite on the map

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