PACHNOLITE

    Class : Halides
    Subclass : Fluorides
    Crystal system : Monoclinic
    Chemistry : NaCaAlF6 H2O
    Rarity : Rare

Pachnolite is a secondary fluoride which is found in fluorinated pegmatites, and exceptionally in carbonatite. Its name comes from the Greek pachne (frost) because of its transparent appearance like ice. Pachnolite forms elongated, constantly twinned prisms measuring up to 8 cm, grainy and cleavable masses, sometimes stalactites or chalcedony-like masses; it is colorless or white. Pachnolite is commonly associated with other pegmatite fluorides (elpasolite, cryolite, sellaite, fluorite, etc...).

Main photo : Pachnolite from Ivigtut Mine, Greenland © Christian Rewitzer

Pachnolite in the World

The most beautiful specimens of pachnolite have been extracted from the famous pegmatite of Ivigtut (Greenland) where it is formed by alteration of cryolite. It is known in some other pegmatites famous for their mineralogy such as that of Hagendorf (Bavaria, Germany), Pike's Peak (Colorado) and Lake Gjerdingen (Norway). Finally, it is known in the carbonatite of Goldie (Colorado).

Right photo : Pachnolite from Ivigtut Mine, Greenland © Stephan Wolfsried

Pachnolite in France

Pachnolite is not present in the French underground.

Twinning

Twins are common on {100}, producing crystals with an orthorhombic appearance.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 3
Density : 2.983
Fracture : Irregular
Streak : White

TP : Translucent to transparent
RI : 1.411 to 1.420
Birefringence : 0.009
Optical character : Biaxial +
Pleochroism : None
Fluorescence : None

Solubility : Sulfuric acid

Magnetism : NoneRadioactivity : None