tetragonal Nesosilicates
Zircon
ZrSiO4
Crystal Structure
#! Species: Zircon
#! System: Tetragonal (4/mmm)
#! Habit: Tetragonal prism with dipyramid
tetragonal[4/mmm]:{100}@1.0 + {101}@0.8
tetragonal
4/mmm
{100} {101}
Quick Facts
Hardness
7.5
Specific Gravity
4.6
Refractive Index
1.925
Optical Character
Uniaxial +
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Open in PlaygroundPhysical Properties
Crystal Systemtetragonal
Hardness (Mohs)7.5
Specific Gravity4.6
CleavageImperfect
FractureConchoidal
LustreAdamantine to vitreous
Optical Properties
Refractive Index1.925
Birefringence0.059
Optical CharacterUniaxial +
Dispersion0.039
Pleochroismweak: Body color / Lighter shade (Blue zircon shows colorless/blue dichroism; weak in most colors)
FluorescenceUsually inert; some weak yellow-orange
Colours
Blue (heated)ColorlessGolden/yellowBrownGreen (metamict)RedOrange
Localities
Cambodia (Ratanakiri)MyanmarSri LankaTanzaniaVietnamAustralia
Common Inclusions
Parallel growth linesDoublet reflections (from birefringence)Apatite crystalsMonazite crystalsMetamict texture (treacle effect)
Known Treatments
Heat treatment (to blue, colorless, golden)
Crystal Forms
tetragonal_prismtetragonal_dipyramid
Diagnostic Features
Very high RI and dispersion; strong doubling (high type); metamict varieties exist
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Open in PlaygroundRelated Minerals
Other minerals in the tetragonal system
