RAUENTHALITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated arsenates
    Crystal system : Triclinic
    Chemistry : Ca3(AsO4)2 10H2O
    Rarity : Very rare

Rauenthalite is a very rare mineral that was discovered at level -40 of the Gabe-Gottes vein, in the Ste-Marie-aux-Mines mine (Haut-Rhin), near another newly formed calcium arsenate : sainfeldite. Rauenthalite results from the dehydration of phaunouxite, which then loses a molecule of water. Its name comes from its discovery location : the Gabe-Gottes veins in the Rauenthal valley (Haut-Rhin). Rauenthalite occurs as small, irregular snow-white balls or irregular aggregates of very fine crystals, commonly associated with picropharmacolite. The size of these groupings does not exceed a few millimeters. Unlike other calcium arsenates, rauenthalite never adopts a fibroradiated arrangement.

Main photo : Rauenthalite from Clara Mine, Germany © Michael Förch

Rauenthalite from Clara Mine, Germany © Michael Förch
Rauenthalite from Clara Mine, Germany © Volker Heck
Rauenthalite from Dionýz mine, Slovakia © Martin Stevko
Rauenthalite from Giftgrube, Ste-Marie-aux-Mines, Haut-Rhin, France © Henry Minot

Rauenthalite in the World

Rauenthalite is known in Germany at the Anton Mine near Heubachtal in the Black Forest, in a deposit of silver, copper and arsenic similar to that of Ste-Marie-aux-Mines. It is also reported at the Clara Mine, at St-Andréasberg, in Laurion (Greece), at the Muckross Mine (Ireland), at the Dionýz Mine (Slovakia), at the Ivy Tor Mine (Great Britain), at Jáchymov (Czech Republic) and at Mohawk Mine (Michigan) and at Getchell Mine (Nevada).

Rauenthalite in France

In France, rauenthalite is present at Gabe-Gottes (Haut-Rhin), the type locality of the species as well as in several deposits of Ste-Marie-aux-Mines. It is also known at Salsigne (Aude).

Twinning

No known twinning for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 2
Density : 2.36
Fracture : Irregular
Streak : White

TP : Transparent
RI : 1.540 to 1.576
Birefringence : 0.030
Optical character : Biaxial +
Pleochroism : None
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : None