PHARMACOLITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated arsenates
    Crystal system : Monoclinic
    Chemistry : CaHAsO4 2H2O
    Rarity : Uncommon


Pharmacolite is a common oxidation mineral of native arsenic; it forms in replacement of arsenolite when the environment is sufficiently rich in calcium. This mineral also appears in the old galleries of arsenic deposits, it is also known in certain industrial slags. Its name comes from the Greek pharmakon (remedy, poison), due to the arsenic contained in the mineral. It is relatively easy to recognize when it is in its usual form of transparent to white or grayish acicular crystals, grouped in rosettes or spherolites, measuring up to 2 cm. It is less easy to identify when it occurs in botryoidal or stalactitic clusters.

Main photo : Pharmacolite from Baia Sprie, Romania © Vilhelm Faragó

Pharmacolite & realgar from Saru Dornei, Romania © Elmar Lackner
Pharmacolite from Sauberg Mine, Saxony, Germany © Stephan Wolfsried
Pharmacolite from Jáchymov, Czech Republic © Gianfranco Ciccolini
Pharmacolite from Giftgrube, Ste-Marie-aux-Mines, Haut-Rhin, France © Jean-Marie Claude

Pharmacolite in the World

Pharmacolite is relatively classic in arsenic veins on all continents. It is particularly well represented in the German veins of Saxony and Lower Saxony (St-Andréasberg, Schneeberg), Nevada (Getchell) associated with realgar, Morocco (Bou Azzer), Iran (Talmessi), Lavrion (Greece) and Czech Republic (Jachymov, where beautiful crystals were discovered). The most beautiful crystals undoubtedly come from Baia Sprie (Romania) and measure up to 7 cm.

Pharmacolite in France

In France, pharmacolite is known in good specimens in the arsenic veins of Ste-Marie-aux-Mines (Haut-Rhin), at Mas d'Alary (Hérault), at Lucéram (Alpes-Maritimes) and in the slag of Villanière (Aude).

Twinning

No twin known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.



Hardness : 2 to 2.5
Density : 2.53 to 2.73
Fracture : Irregular
Streak : White


TP : Translucent to transparent
RI : 1.580 to 1.594
Birefringence : 0,010
Optical character : Biaxial -
Pleochroism : None
Fluorescence : Pale blue


Solubility : Acids

Magnetism : NoneRadioactivity : None