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

Paraiba Tourmaline

When Paraba tourmaline was first discovered in Brazil in the 1980's, the unusually intense "neon" or "electric" blues and greens set it apart from any other tourmaline previously known. The color of this gem ranges from intense emerald green through vivid Caribbean blue to a rich sapphire blue. Apart from its intense colors, another key feature of Paraba tourmaline is its relative lack of extinction, best described as a lifeless area within a stone.

Colors

Bright Electric Blue To Green, Violet To Purplish

  • Paraiba-tourmaline classification

    CommonName
    Paraiba Tourmaline
    Species
    Elbaite
    Variety
    Paraiba Tourmaline
    Colors
    Bright Electric Blue To Green, Violet To Purplish
    AlternateNames
    GemstoneGroups
    Tourmaline
    KeySeparations
    appearance, refractive index and high birefringence; then optic figure, pleochroism and specific gravity. Has intense saturated color.
    ClassificationComments
    Crystal habit is prismatic and may be 3, 6 or 9-sided; often a triangular prism with convex faces, and often long and heavily striated parallel to the c axis. Pyramidal terminations are common. Tourmaline is part of an isomorphous series.Cuprian Elbaite must have copper present to be called Paraiba tourmaline.Originally found in the Brazilian State of ParaibaDark material might have a birefringence as high as 0.040.
  • Paraiba-tourmaline chemistry & crystallography

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

    Transparency
    Transparent
    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
  • Paraiba-tourmaline characteristic physical properties

    Hardness
    7-7.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3-3.26 Range:0.2/-0.06 Typical:3.06
    Toughness
    Good
    Inclusions
    Paraiba tourmaline is a type II clarity stone. 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
    Cleavage
    Poor, in two directions