Bowenite

Bowenite (Serpentine)
Chemical composition	Mg6((OH)8)Si4O10)
Crystal system	Mostly monoclinic
Habit	Cryptocrystalline
Cleavage	None
Fracture	Even to hackly
Hardness	2-5.5
Optic nature	None
Refractive index	±1.55
Birefringence	None
Dispersion	None
Specific gravity	2.59
Lustre	Waxy
Pleochroism	None