Dickite
Chemical Formula	Al2Si2O5(OH)4
Species	Silicates
Crystal System	Monoclinic
Mohs Scale	2
Specific Gravity	2.6
Color	White, with coloration from impurities
Streak	White
Luster	Satiny to pearly
Refractive Index	n = 1.561 - 1.564 n = 1.561 - 1.566 n = 1.566 - 1.570
Diaphaneity	Transparent
Cleavage	PerfectOn , perfect.
Crystal Habit：Pseudohexagonal crystals, aggregates of platelets and compact massive
Geological Setting：Usually of hydrothermal origin in conjuncton with veins, derived in part from the alteration of aluminosilicate minerals; also occurs as an authigenic sedimentary phase.