LithoCat

MineralChestermanite
FormulaMg2(Fe3+,Mn3+,Al,Sb3+)(BO3)O2  
Crystal FormOrthorhombic/Dipyramidal [2/m 2/m 2/m]
ColorGrayish-green to black
Density3.6 – 3.7 g/cm3
FractureIrregular/Uneven, Conchoidal
Hardness6.0
LustreVitreous, Silky
StreakPale grayish green
Type Loc.Unnamed Skarn occurrence [1], Kaiser Wilderness area, Fresno Co., CA, USA
Dana 8 Class24.2.1.5
Strunz Class6.AB.40
Mindatmindat.org
WebMineralWebMineral
ID522