These characteristics are only generalities and can not be used as dependable identifying traits. Absolute identification can not be made by ordinary means. Color is clear or white. Luster is vitreous. Also nodules, fibrous and earthy masses.
Cleavage is perfect in two directions, prismatic.
Cleavage is rarely seen due to small crystal size. Fracture is conchoidal to uneven. Hardness is 5 - 5.5. Streak is white. Associated Minerals are quartz , apophyllite , datolite , heulandite , stilbite and other zeolites .