Watermelon Tourmaline Gemstone & Information | Gemopedia by JTV | Gemopedia™

Watermelon Tourmaline

Watermelon tourmaline is an interesting multi-colored elbaite variety. Gems are usually fashioned in thin polished slices to display the crystal's concentric color rings. If you use your imagination, the green represents the skin of the watermelon, white makes up the rind, and pink is the sweet fruit. Incredibly, the colors of watermelon tourmaline are 100% natural, a rare occurrence in nature that makes the gem highly collectable.

Colors

Pink Center With Green Edges

  • Watermelon-tourmaline classification

    CommonName
    Watermelon Tourmaline
    Species
    Tourmaline
    Variety
    Watermelon Tourmaline
    Colors
    Pink Center With Green Edges
    AlternateNames
    GemstoneGroups
    KeySeparations
    appearance, refractive index and high birefringence; then optic figure, pleochroism and specific gravity
    ClassificationComments
    Not all watermelon 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.
  • Watermelon-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
  • Watermelon-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, medium to strong, varying shades of body color
  • Watermelon-tourmaline characteristic physical properties

    Hardness
    7-7.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3-3.26 Typical:3.06
    Toughness
    Good
    Inclusions
    Watermelon tourmaline is Type II clarity stone. Color zoning with pink core and green edges. 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