Helvite
Chemical Formula	Mn4Be3SiO43S
Species	Silicates
Crystal System	Isometric
Mohs Scale	6
Specific Gravity	3.2-3.44
Color	Golden yellow, brown, red, gray-yellow, yellow-green
Streak	White
Luster	Vitreous, Resinous
Refractive Index	n = 1.728 - 1.749
Diaphaneity	Translucent
Cleavage	Distinct/GoodDistinct on
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Tetrahedra, dodecahedra, octahedra
Geological Setting：Granites, pegmatites, gneisses, contact zones, skarns.