hexagonal Cyclosilicates
Beryl (Hexagonal Prism)
Be3Al2Si6O18
Quick Facts
Hardness
7.5
Specific Gravity
2.67
Refractive Index
1.577
Optical Character
Uniaxial -
Crystal Structure
#! Species: Beryl
#! System: Hexagonal (6/mmm)
#! Habit: Hexagonal prismatic
hexagonal[6/mmm]:{10-10}@1.0 + {0001}@1.0
hexagonal
6/mmm
{10-10} {0001}
Physical Properties
Crystal Systemhexagonal
Hardness (Mohs)7.5
Specific Gravity2.67
CleavageImperfect basal (rarely seen)
FractureConchoidal to uneven
LustreVitreous
Optical Properties
Refractive Index1.577
Birefringence0.005-0.009
Optical CharacterUniaxial -
Dispersion0.014
PleochroismWeak to distinct (varies by variety)
Colours
Green (emerald)Blue (aquamarine)Pink (morganite)Yellow (heliodor)Colorless (goshenite)Red (red beryl)
Localities
ColombiaBrazilZambiaPakistanMadagascarAfghanistanRussia (Urals)Nigeria
Common Inclusions
Three-phase (Colombian emerald)Actinolite needles (Zambian emerald)Rain/parallel tubes (aquamarine)Liquid feathersTwo-phase inclusionsMineral crystals
Known Treatments
Oiling (emerald)Heat treatment (aquamarine, morganite)Fracture filling (emerald)
Crystal Forms
hexagonal_prismpinacoiddihexagonal_prismhexagonal_dipyramid
Interactive Preview
Open this crystal in the CDL Playground to rotate, export, and explore in 3D.
Open in Playground #! Species: Beryl
#! System: Hexagonal (6/mmm)
#! Habit: Hexagonal prismatic
hexagonal[6/mmm]:{10-10}@1.0 + {0001}@1.0
Related Minerals
Other minerals in the hexagonal system
