Luster is vitreous. Crystals are transparent to translucent. Crystal Habits include druses of prismatic crystals with a distinctly monoclinic slant. Also pseudo-cubic crystals are common. Cleavage is perfect.
Fracture is conchoidal.
Streak is white. Associated Minerals include pachnolite , cryolite , ralstonite and limonite . Notable Occurrences are limited to Ivigtut, Greenland and other southwestern Greenland localities. Best Field Indicators are crystal habit, softness, associations, locality and good cleavage.