Multi-Colored Tourmaline Gemstone & Information | Gemopedia by JTV | Gemopedia™

Multi-Colored Tourmaline

Multi-colored tourmaline is a variety of tourmaline containing two or more colors displayed in one crystal. Green and pink is the most prevalent combination, but others are possible. Multi-colored tourmaline may be referred to as "bi-colored tourmaline" or "tri-colored tourmaline," etc.

Colors

Variations Of Two, More Colors Usually Green, Blue, Red

  • Multi-colored-tourmaline classification

    CommonName
    Multi-Colored Tourmaline
    Species
    Elbaite
    Variety
    Colors
    Variations Of Two, More Colors Usually Green, Blue, Red
    AlternateNames
    Parti-Colored Tourmaline, Bi-Color Tourmaline, Tri-Color Tourmaline
    GemstoneGroups
    Tourmaline
    KeySeparations
    appearance, refractive index and high birefringence; then optic figure, pleochroism and specific gravity
    ClassificationComments
    Not all multi-colored tourmaline is elbaite tourmaline Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH).Dark material might have a birefringence as high as 0.040.Pyroelectric: development of opposite charges at the ends of a tourmaline crystal due to change in temperature. Piezoelectric: development of opposite charges at the ends of a tourmaline crystal when placed under stress.
  • Multi-colored-tourmaline chemistry & crystallography

    ChemicalName
    complex boro-silicate of Al, Mg and Fe
    ChemicalFormula
    Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
    Synthesis
    CrystalSystem
    Trigonal
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Multi-colored-tourmaline optical properties

    Transparency
    Transparent - Translucent
    Dispersion
    Strength: moderate fire Value: 0.017
    OpticalComments
    RefractiveIndex
    1.624-1.644
    Tolerance:-1.22222222222222
    Birefringence
    0.018-0.02
    OpticCharacter
    Uniaxial
    OpticSign
    Negative
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Variable
    LWUV: Variable
    CCFReaction
    Pleochroism
    Dichroic, moderate to strong, varying shades of body color
  • Multi-colored-tourmaline characteristic physical properties

    Hardness
    7-7.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3-3.26 Typical:3.06
    Toughness
    Good
    Inclusions
    Multi-colored tourmaline is Type II clarity stone. Stones will have two or more color zones. Stones might contain liquid and gas inclusions that are long and thin, reflective gas-filled fractures and color zoning.
    Luster
    Vitreous
    Stability
    Very Good
    Fracture
    Conchoidal, Subconchoidal, Irregular, Uneven
    Cleavage
    Poor, in two directions