Labradorite (labradorescent) Gemstone & Information | Gemopedia by JTV | Gemopedia™

Labradorite (labradorescent)

Displaying brilliant pastels and deep golden colors, labradorite features a spellbinding "black rainbow" of color. When appreciating the iridescent play of colors known as labradorescence, observe the strength and intensity by viewing from different angles, as different colors or even a range of colors may be visible from different positions.

Colors

Gray To Almost Black With Blue, Green Interference Colors

  • Labradorite-labradorescent classification

    CommonName
    Labradorite (labradorescent)
    Species
    Labradorite
    Variety
    Colors
    Gray To Almost Black With Blue, Green Interference Colors
    AlternateNames
    Spectrolite
    GemstoneGroups
    Feldspar
    KeySeparations
    Appearance, RI, birefringence, optic character and magnification
    ClassificationComments
    Stones display labradorscence or blue and green interference colors.Spectrolite is the trade name for labradorite from Finland and has rainbow labradorscence.
  • Labradorite-labradorescent chemistry & crystallography

    ChemicalName
    calcium or sodium silicate
    ChemicalFormula
    NaAlSi3O8 or CaAl2Si2O8
    Synthesis
    CrystalSystem
    Triclinic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Labradorite-labradorescent optical properties

    Transparency
    Translucent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.559-1.568
    Tolerance:(+0.005/-0.005)
    Birefringence
    0.009
    OpticCharacter
    Biaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert to weak white
    LWUV: Inert to weak white
    CCFReaction
    Pleochroism
    None
  • Labradorite-labradorescent characteristic physical properties

    Hardness
    6-6.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.65-2.75 Typical:2.7
    Toughness
    Poor
    Inclusions
    Labradorite might show repeated twinning, black magnetite needle like inclusions, ilmenite, and metallic platelets that might be hematite.
    Luster
    Vitreous
    Stability
    Good
    Fracture
    Uneven, Splintery
    Cleavage
    Perfect, in two directions