Petalite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Petalite

Faceted petalite gems and specimens are prized by gemstone and mineral collectors. Petalite's name is derived from the Greek petalos (leaf), referring to its perfect cleavage. Colorless material is common, and large crystals have been mined. Other petalite colors include white to yellow or gray, yellowish green to light green and pink. Crystals range from transparent to translucent and are prized for their good clarity. Faceted gems aren't often seen due to petalite's cleavage planes.

Colors

Colorless, Gray, Yellow, Pink, Very Light Green

  • Petalite classification

    CommonName
    Petalite
    Species
    Petalite
    Variety
    Colors
    Colorless, Gray, Yellow, Pink, Very Light Green
    AlternateNames
    Castorite, Pollucite
    GemstoneGroups
    KeySeparations
    RI, birefringence, optic sign and SG
    ClassificationComments
  • Petalite chemistry & crystallography

    ChemicalName
    lithium aluminum silicate
    ChemicalFormula
    LiAlSi4O10
    Synthesis
    CrystalSystem
    Monoclinic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Petalite optical properties

    Transparency
    Transparent - Translucent
    Dispersion
    OpticalComments
    RefractiveIndex
    1.504-1.516
    Tolerance:(+0.006/-0.002)
    Birefringence
    0.12-0.16
    OpticCharacter
    Biaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert
    LWUV: Inert to weak orange
    CCFReaction
    Pleochroism
    Unobservable
  • Petalite characteristic physical properties

    Hardness
    6-6.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.39-2.46 Typical:2.4
    Toughness
    Poor
    Inclusions
    Luster
    Vitreous
    Stability
    Fracture
    Subconchoidal
    Cleavage
    Perfect, in one direction, Poor, in one direction