MITRIDATITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated phosphates
    Crystal system : Monoclinic
    Chemistry : Ca2Fe3O2(PO4)3 3H2O
    Rarity : Uncommon

Mitridatite is a secondary phosphate formed by meteoric alteration of primary iron-bearing phosphates (triphylite, lithiophilite, vivianite). It is found in coatings or encrustations in pegmatites, in oolitic phosphate iron ores, sometimes in phosphate soils. Its name comes from its location of discovery : the Mithridat Mountains (Crimea, Ukraine). Mitridatite rarely occurs in tabular crystals of 2 mm maximum. It is much more common in masses, nodules and veinlets. Its color is variable with a dominant of dark greens, passing to green-yellow in the fine-grained aggregates.

Main photo : Mitridatite from Cigana claim, Barra do Cuieté, Minas Gerais, Brazil © Sergio Varvello

Mitridatite in the World

Mitridatite is known in coatings and mases in most American phosphate pegmatites of the Black Hills, in South Dakota (Custer district: Bull Moose, Tip Top, White Elephant...) and in New Hampshire (Palermo) , associated with many other primary and secondary phosphates. It is also present in phosphate pegmatites from Germany (Hagendorf), Portugal (Mangualde, Sabugal), and Namibia (Karibib). Mitridatite is also present in oolitic phosphate iron deposits in Crimea (Ukraine) and Russia (Taman region).

Right photo : Mitridatite from Hagendrof, Bavaria, Germany © Stephan Wolfsried


Mitridatite in France

In France, mitridatite is known in Echassières as well as in the pegmatites of Collioure (Pyrénées-Orientales).

Twinning

Twins are known by rotation perpendicular to {100}.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 2.5
Density : 3.25
Fracture : Irregular
Streak : Light green

TP : Translucent to opaque
RI : 1.785 to 1.850
Birefringence : 0.065
Optical character : Biaxial -
Pleochroism : None
Fluorescence : None

Solubility : Acids

Magnetism : NoneRadioactivity : None