monoclinic Inosilicates
Diopside
CaMgSi2O6
Crystal Structure
#! Species: Diopside
#! System: Monoclinic (2/m)
#! Habit: Short prismatic with well-developed pinacoid
monoclinic[2/m]:{110}@1.0 + {100}@0.6 + {010}@0.5 + {001}@0.9
monoclinic
2/m
{110} {100} {010} {001}
Quick Facts
Hardness
5.5
Specific Gravity
3.22
Refractive Index
1.675
Optical Character
Biaxial +
Physical Properties
Crystal Systemmonoclinic
Hardness (Mohs)5.5
Specific Gravity3.22
CleavageGood {110} at 87-93 degrees (characteristic pyroxene cleavage)
FractureUneven to conchoidal
LustreVitreous
Optical Properties
Refractive Index1.675
Birefringence0.024-0.030
Optical CharacterBiaxial +
Dispersion0.02
Pleochroismmoderate: Light green / Dark green (Strong in chrome diopside; weak in other varieties)
FluorescenceStrong blue to bluish-white (SWUV)
Colours
Green (chrome diopside)ColorlessPale greenDark greenViolet-blue (violan)BrownBlack
Localities
Russia (Siberia - chrome diopside)Italy (Piedmont)Austria (Zillertal)TanzaniaMadagascarPakistanIndia (star diopside)
Crystal Forms
prismpinacoid
Related Minerals
Other minerals in the monoclinic system
Actinolite (Prismatic)
Ca2(Mg,Fe)5Si8O22(OH)2
Augite (Prismatic)
(Ca,Na)(Mg,Fe,Al)(Si,Al)2O6
Azurite
Cu3(CO3)2(OH)2
Chrome Diopside
CaMg1-xCrxSi2O6
Crocoite
PbCrO4
Dyed Howlite (Turquoise Simulant) (Dyed Howlite (Blue))
Ca2B5SiO9(OH)5 (calcium borosilicate hydroxide; dyed blue to simulate turquoise)