Chrysoberyl Gemstone & Information | Gemopedia by JTV | Gemopedia™

Chrysoberyl

Chrysoberyl is the name of a mineral as well as three different gem varieties--two of which are widely accepted as some of the most rare and valuable of all phenomenal gems. The gem commonly known as chrysoberyl is a yellowish-green, brownish-yellow, or colorless transparent to translucent mineral that is usually faceted into gems and generally considered a collector's stone. While not often set in jewelry, its characteristics make it ideal for such use. When chrysoberyl displays color-change properties, it is known as alexandrite, and when it exhibits chatoyancy, it is known as cat's eye chrysoberyl.

Colors

Yellow To Yellowish Green, Greenish Brown, Bluish Green

  • Chrysoberyl classification

    CommonName
    Chrysoberyl
    Species
    Chrysoberyl
    Variety
    Colors
    Yellow To Yellowish Green, Greenish Brown, Bluish Green
    AlternateNames
    GemstoneGroups
    KeySeparations
    refractive index, birefringence, pleochroism and spectrum. Spectrum should reflect a strong diagnostic band at 444nm.
    ClassificationComments
    Phenomenal chrysoberyl may exhibit chatoyancy, in which case it is classified as "cat's-eye chrysoberyl." Misnomer: oriental chrysolite.
  • Chrysoberyl chemistry & crystallography

    ChemicalName
    beryllium aluminum oxide
    ChemicalFormula
    BeAl2O4
    Synthesis
    CrystalSystem
    Orthorhombic
    ChemistryClassification
    Oxide
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Chrysoberyl optical properties

    Transparency
    Transparent - Opaque
    Dispersion
    Strength: weak fire Value: 0.015
    OpticalComments
    RefractiveIndex
    1.746-1.755
    Tolerance:(+0.004/-0.006)
    Birefringence
    0.008-0.01
    OpticCharacter
    Biaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert to yellowish green in yellow and greenish stones
    LWUV: Could be red for "mint" chrysoberyl
    CCFReaction
    Pleochroism
    Trichroic, weak
  • Chrysoberyl characteristic physical properties

    Hardness
    8.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3.71-3.75 Range:+/-0.02 Typical:3.73
    Toughness
    Varies
    Inclusions
    Transparent green and yellow chrysoberyl are type I clarity stones. Stones might show twinning planes, feathers, fingerprints, silk, elongated tubes and needles.
    Luster
    Bright Vitreous
    Stability
    Very Good
    Fracture
    Conchoidal
    Cleavage
    Good, in one direction