Beryl

Beryl is a beryllium aluminium silicate with the chemical formula Be3Al2(SiO3)6. The hexagonal crystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare.

Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, red, and white.

Source: http://en.wikipedia.org/wiki/Beryl

 

 

Beryl Properties

Chemical Composition: 
Beryllium Aluminium Silicate (Be3Al2(SiO3)6; Trace elements are Cr, V, Fe, Mn, etc.
Colors / Varieties: 
  • Green - Emerald (Cr/V/Fe)
  • Green - Green Beryl (No Chromium)
  • Colorless - Goshenite
  • Blue - Aquamarine
  • Yellow - Yellow Beryl
  • Golden - Heliodor
  • Pink - Morganite
  • Red - Red Beryl
  • Deep blue (fading) - Maxixe Beryl
  • Chatoyant - Cat's eye beryl
  • Asteriated - Star beryl
  • Parti-colored beryl
  • Trapiche emerald - green with black spokes intersecting.
Crystal System / Forms: 
Hexagonal System / Generally as six-sided prisms with pyramidal and / or pinacoidal terminations. As such columnar prismatic habits are common.
Hardness: 
7.5 - 8
Specific Gravity: 
2.68 - 2.80
Cleavage / Fracture: 
Poor cleavage / parting parallel to the basal plane.
Optic Character: 
Anisotropic, D.R.; Uniaxial Negative.
Lustre: 
Vitreous.
Refractive Index / Birefringence: 
1.577 - 1.583 / 0.006 - 0.009. R.I. Range: 1.57 - 1.60
Pleochroism: 
Distinct dichroism depending on depth of color.
Magnification: 
Parallel two phase or rain inclusions, three phase and crystalline inclusions, fingerprints, hexagonal growth zoning.
U.V. Fluorescence: 
Variable.
Spectrum: 
  • Fading blue maxixe beryl: bands at 695nm & 655nm with weaker bands at 628nm, 615nm, 581nm and 550nm.
  • Green and yellow beryl, pink beryl: spectrum is not well pronounced.
Treatment (Enhancement): 
Synthesis: 
Flux fusion and hydrothermal method (not commercially available)
Simulants (with separation tests): 
Yellow beryl: Citrine (optic figure, R.I.), Scapolite (R.I., birefringence, U.V. fluorescence, doubling), glass (optic character), hessonite garnet (R.I., S.G., inclusions), Topaz (R.I., S.G.), Labradorite (R.I., inclusions, U.V. fluorescence), Sillimanite (R.I., S.G., inclusions).
Geological Occurrence: 
Granitic rocks - pegmatite and schists, in hydrothermal veins and metamorphic limestone.
Sources: 
Morganite: Madagascar, U.S.A. (California, Utah), India (Orissa), Pakistan.
Cuts & Uses: 
Facetted cuts, cabochons, beads, carvings, etc.