Halotrichite
Chemical Formula	FeAl2(SO4)4·22H2O.
Species	Sulfates
Crystal System	Monoclinic
Mohs Scale	1-2
Specific Gravity	1.89
Color	Colourless to white, yellowish, greenish; colourless in transmitted light.
Luster	Vitreous
Refractive Index	n = 1.480 n = 1.486 n = 1.490
Diaphaneity	Transparent, Translucent
Cleavage	Poor/IndistinctOn , poor.
Fracture	Conchoidal
Crystal Habit：Crystals acicular ; distinctly terminated crystals rare. Radial or matted aggregates of hair-like crystals; tufted; spheroidal; as incrustations or effloresences; asbestiform. Larger crystals may be hollow or contain bubbles of liquid or gas.