LithoCat

MineralHolmquistite
FormulaLi[(Mg,Fe2+)3Al2]Si8O22(OH)2
Crystal FormOrthorhombic/Dipyramidal [2/m 2/m 2/m]
CleavagePerfect on {210}, intersecting at ~54 and ~126 deg.
ColorBlack, dark violet to light sky-blue; pale yellow to violet in thin section
Density3.0 – 3.1 g/cm3
DiaphaneityTransparent to translucent
Hardness5.0 - 6.0
LustreVitreous
StreakWhite, with sky-blue tinge
Dana 8 Class66.1.2.9
Strunz Class8/F.12-20
Mindatmindat.org
WebMineralWebMineral
ID253