tetragonal Nesosilicates
Vesuvianite
Ca19(Al,Mg)13(SiO4)10(Si2O7)4(OH,F)10
Quick Facts
Hardness
6.5
Specific Gravity
3.32
Refractive Index
1.7
Optical Character
Uniaxial - (occasionally +)
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Open in PlaygroundCrystal Structure
#! Species: Vesuvianite (Idocrase)
#! System: Tetragonal (4/mmm)
#! Habit: Prismatic with pinacoid
tetragonal[4/mmm]:{100}@1.0 + {110}@0.8 + {001}@0.6
tetragonal
4/mmm
{100} {110} {001}
Physical Properties
Crystal Systemtetragonal
Hardness (Mohs)6.5
Specific Gravity3.32
CleavagePoor {110}
FractureSubconchoidal to uneven
LustreVitreous to resinous
Optical Properties
Refractive Index1.7
Birefringence0.001-0.025
Optical CharacterUniaxial - (occasionally +)
Dispersion0.019
PleochroismWeak
Colours
Green (most common)Yellow-greenYellow-brownBrownBlue (cyprine - copper-bearing)Violet
Localities
Italy (Mount Vesuvius - type locality)Canada (Quebec, British Columbia)Russia (Ural Mountains)USA (California)KenyaPakistan
Common Inclusions
Colour zoningCrystal inclusions
Crystal Forms
tetragonal_prismpinacoid
Notes
Named by Werner in 1795 for crystals from Mount Vesuvius; gemologists often use the older name idocrase
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Open in PlaygroundRelated Minerals
Other minerals in the tetragonal system
