(Na,Ca)8(AlSiO4)6(SO4,S,Cl)2Cubic
Lapis Lazuli
(Na,Ca)8(AlSiO4)6(SO4,S,Cl)2
SilicatesChemical Formula(Na,Ca)8(AlSiO4)6(SO4,S,Cl)2
Crystal SystemCubic
Mohs Hardness5.5
Specific Gravity2.4
ColorDeep blue, greenish blue
LusterVitreous to greasy
StreakBlue
CleavageNone
FractureUneven
Occurrence
Found in metamorphic limestone. Prized since antiquity. Ultramarine pigment source.