The Beauty Beryl

Beryl

  • named after the latin word beryllus or greek word beryllos, respectively, which is referred to “precious blue-green color-of-sea water stone”
  • the first lenses were made of beryl, as glass could not be made clear enough; this is the origin of the German word for glasses, i.e. “Brille”
  • there are important varieties, namely the blue Aquamarine (Fe2+ impurities), the Green Emerald (Cr3+ impurities), the Golden Beryl (Fe3+ impurities), the Pink or Rose Beryl named Morganite (after the financier J.P. Morgan, containing Mn2+ impurities), and the Red beryl
  • Formula: Al2Be3Si6O18
  • Space group: P6/mmc (No. 192)
  • Crystal system: hexagonal
  • Crystal class: 6/mmm
  • Lattice parameters: a = b =  9.219 Å, c = 9.198 Å, α = β = 90°, γ  120°

beryl-aquamarin_118278

Picture: Aquamarine, Rob Lavinsky, iRocks.com – CC BY-SA 3.0


beryl-quartz-emerald-zambia-33mm_0885

Picture: Emerald, Rob Lavinsky, iRocks.com – CC BY-SA 3.0


beryl-gold_beryl_tt64a

Picture: Golden Beryl, Rob Lavinsky, iRocks.com – CC BY-SA 3.0


beryl-albite_morganit-197426

Picture: Morganit, Rob Lavinsky, iRocks.com – CC BY-SA 3.0


beryl-red-beryl-196800

Picture: Red Beryl, Rob Lavinsky, iRocks.com – CC BY-SA 3.0


Crystal structure (click on the picture to download the VESTA file):

beryl

(K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” J. Appl. Crystallogr., 44, 1272-1276 (2011).)

  • yellow: SiO4 tetrahedra, six tetrahedra are corner-connected to form a ring
  • green: distorted BeO4 tetrahedra
  • blue: slightly distorted AlO6 octahedra
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