Labradorite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Labradorite

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

Colorless, Weak Green To Yellowish Green, Yellow, Orange To Brown, Brownish Red, Oregon Material Pale To Pinkish Orange, Pink To Reddish Orange, Red-Orange, Deep Red, Pale Yellow To Orange, Moderate To Strong Green Sometimes Bi-Color

  • Labradorite classification

    CommonName
    Labradorite
    Species
    Labradorite
    Variety
    Colors
    Colorless, Weak Green To Yellowish Green, Yellow, Orange To Brown, Brownish Red, Oregon Material Pale To Pinkish Orange, Pink To Reddish Orange, Red-Orange, Deep Red, Pale Yellow To Orange, Moderate To Strong Green Sometimes Bi-Color
    AlternateNames
    GemstoneGroups
    Feldspar
    KeySeparations
    RI, birefringence, optic character and magnification
    ClassificationComments
    Labradorite often shows twinning in the polariscope. If stones show aventurescence the variety is sunstone or aventurine feldspar. Oregon material might have a RI of 1.563 to 1.572 and SG of 2.67 to 2.72. Oregon material might be called sunstone even when it does not display aventurescence. Misnomers: Rainbow moonstone
  • Labradorite chemistry & crystallography

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

    Transparency
    Semitransparent - Translucent
    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
    Dichroic, colorless and light yellow
  • Labradorite characteristic physical properties

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