Pachnolite Locality: Ivigtut Cryolite deposit, Ivittuut (Ivigtut) , Arsuk Firth, Arsuk , Kitaa (West Greenland) Province, Greenland ( Locality at mindat.org ) Picture width 1.5 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Pachnolite
Pachnolite is an IMA-recognized mineral species in the halide class, with the chemical formula NaCaAlF₆·H₂O.
It crystallizes in the monoclinic crystal system (space group F2/d).
Key properties: Mohs hardness 3; specific gravity 2.96–3.01; Vitreous luster; optically biaxial.
IMA symbol Phn, grandfathered status — known before the IMA’s founding, named in 1863.
Occurs as an alteration product of cryolite and other alkali aluminum fluorides, most commonly in pegmatites.
It is found associated with Cryolite, thomsenolite, chiolite, elpasolite, ralstonite, sellaite, fluorite.
Its name comes from the Greek for frost and stone, in allusion to its appearance.