hexagonal Cyclosilicates
Emerald
Be3Al2(SiO3)6:Cr
Crystal Structure
#! Species: Emerald (Beryl)
#! System: Hexagonal (6/mmm)
#! Habit: Elongated hexagonal prism with jardin inclusions
hexagonal[6/mmm]:{10-10}@1.0[inclusion:jardin] + {0001}@0.8 | elongate(c:1.5)
hexagonal
6/mmm
{10-10} {0001}
Quick Facts
Hardness
7.5
Specific Gravity
2.72
Refractive Index
1.577
Optical Character
Uniaxial -
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Open in PlaygroundPhysical Properties
Crystal Systemhexagonal
Hardness (Mohs)7.5
Specific Gravity2.72
CleavageIndistinct {0001}
FractureConchoidal to uneven
LustreVitreous
Optical Properties
Refractive Index1.577
Birefringence0.006
Optical CharacterUniaxial -
Dispersion0.014
Pleochroismmoderate: Blue-green / Yellow-green (More visible in darker stones; best seen perpendicular to c-axis)
FluorescenceUsually inert; weak red in some Colombian (LWUV)
Colours
GreenBluish-greenYellowish-green
Localities
ColombiaZambiaBrazilEthiopia
Common Inclusions
JardinThree-phaseCrystalsFissures
Known Treatments
OilingResin fillingSurface coating
Crystal Forms
hexagonal_prismpinacoid
Diagnostic Features
Three-phase inclusions (Colombian); jardin; Chelsea filter reaction in Cr-bearing
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Open in PlaygroundSynthetics & Simulants
Known synthetic and simulant versions of Emerald
Soudé Emerald (Doublet) composite
Flux-Grown Emerald (Crystal) synthetic
Flux
Hydrothermal Emerald (Crystal) synthetic
Hydrothermal
Lechleitner Emerald (Overgrowth) (Overgrowth Crystal) synthetic
Hydrothermal-overgrowth-on-natural-seed (synthetic Hydrothermal Cr+V-rich Beryl Overgrowth Deposited On Natural Colourless Beryl Seed — Goshenite Or Pale Aquamarine)
Related Minerals
Other minerals in the hexagonal system
