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Geosciences LibreTexts

16.04.11: True Blue

  • Page ID
    4041
  • True Blue beryl
    Chemical composition Be3Al2(SiO3)6Beryllium aluminum silicate
    Crystal system Hexagonal
    Habit Prismatic
    Cleavage Poor, basal
    Fracture Conchoidal to uneven
    Hardness 7.5
    Optic nature Uniaxial -
    Refractive index 1.57 - 1.59
    Birefringence 0.004 - 0,009
    Dispersion Low, 0.014
    Specific gravity 2.69
    Lustre Vitreous
    Pleochroism Distinct (shades of body color)

    Discovered in the Yukon, Canada in 2004. An exceptionally dark blue aquamarine, whose color is the result of an extremely high concentration of iron. Unlike the Maxixe beryl, the color is photostable, which means that it is resistant to fading.

    True Blue Beryl is a trade name for medium to dark blue aquamarine from Canada, marketed by True North Gems.