Thomsenolite

Thomsenolite is a mineral with formula: NaCaAlF₆·H₂O. It is an alteration product of cryolite.^[2]

Thomsenolite
Thomsenolite (obelisks) and some pseudocubic ralstonite (picture center)
General
Category	Halide minerals
Formula	NaCaAlF6·H2O
IMA symbol	Tse[1]
Strunz classification	3.CB.40
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	P21/b
Identification
Color	Colourless, white, pale lilac; brownish or reddish tinted due to staining; colourless in transmitted light.
Cleavage	Perfect On {001}; {110} distinct.
Fracture	Irregular/ uneven
Tenacity	Brittle
Mohs scale hardness	2
Lustre	Vitreous, pearly
Streak	White
Diaphaneity	Transparent, translucent
Density	2.981 g/cm3

It was discovered in 1868 in Ivigtut, Greenland and named for Hans Peter Jorgen Julius Thomsen (1826–1909).^[3]