Gahnite
Chemical Formula	ZnAl2O4
Species	Oxides & Hydroxides
Crystal System	Isometric
Mohs Scale	7-8
Specific Gravity	4.38-4.60
Color	Dark green, bluish green, blue to indigo, yellow to brown
Streak	Grey
Luster	Vitreous
Refractive Index	n = 1.79–1.80
Diaphaneity	Translucent to nearly opaque
Cleavage	Indistinct parting on
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Typically octahedra, rarely as dodecahedra also assive to granular