PSEUDOLAUEITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated phosphates
    Crystal system : Monoclinic
    Chemistry : MnFe2(PO4)2(OH)2 8H2O
    Rarity : Very rare

Pseudolaueite is a secondary phosphate resulting from the alteration of other phosphates in complex granitic pegmatites. It is the polymorph of stewartite and laueite. Its name comes from the Greek pseudês (false) and laueite, because we observe a chemical relationship between these two minerals. Pseudolaueite forms thick prismatic or tabular crystals, pseudohexagonal in appearance, 3 mm maximum, of a pale yellow to yellow-orange and brown-orange color.

Main photo : Pseudolaueite from Hagendorf pegmatites, Bavaria, Germany © Christian Rewitzer

Pseudolaueite from Hagendorf pegmatites, Bavaria, Germany © Volker Betz
Pseudolaueite from Hagendorf pegmatites, Bavaria, Germany © Michael Förch
Pseudolaueite from Palermo 1, New Hampshire, USA © Henry Minot
Pseudolaueite from Hagendorf pegmatites, Bavaria, Germany © Stephan Wolfsried

Pseudolaueite in the World

Pseudolaueite is a very rare mineral, observed in some American phosphate pegmatites from South Dakota (White Elephant), New Hampshire (Palermo 1), Sabugal and Mangualde (Portugal); and in those of Hagendorf (Germany). In this last deposit, pseudolaueite crystals encrust and partially replace stewartite crystals, resulting in "mixed" crystals with a stewartite core and pseudolaueite edge.

Pseudolaueite in France

Pseudolaueite is not present in the French underground.

Twinning

No twins known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 3
Density : 2.46
Fracture : Irregular
Streak : White

TP : Translucent to transparent
RI : 1.626 to 1.686
Birefringence : 0.060
Optical character : Biaxial +
Pleochroism : Low
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : None