Willemite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Willemite

Willemite was discovered in 1830 and named after William I, King of the Netherlands. This stone has remarkable luminescent properties. Some specimens glow under an ultraviolet source and continue to glow after the UV light has been removed, a phenomenon called phosphorescence. Specimens that are faceted make beautiful gemstones in blue, yellow, green and brown colors.

Colors

Colorless, Yellow, Greenish-Yellow, Yellow-Green, Orange, Brown, Red, Blue

  • Willemite classification

    CommonName
    Willemite
    Species
    Willemite
    Variety
    Colors
    Colorless, Yellow, Greenish-Yellow, Yellow-Green, Orange, Brown, Red, Blue
    AlternateNames
    GemstoneGroups
    KeySeparations
    RI
    ClassificationComments
  • Willemite chemistry & crystallography

    ChemicalName
    zinc silicate
    ChemicalFormula
    Zn2SiO4
    Synthesis
    CrystalSystem
    Trigonal
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Willemite optical properties

    Transparency
    Transparent - Opaque
    Dispersion
    Strength: weak fire
    OpticalComments
    RefractiveIndex
    1.69-1.723
    Birefringence
    0.028-0.033
    OpticCharacter
    Uniaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Strong green
    LWUV: Weak to strong greenish yellow to green
    CCFReaction
    Pleochroism
    Unobservable
  • Willemite characteristic physical properties

    Hardness
    5.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3.89-4.18
    Toughness
    Poor
    Inclusions
    Luster
    Resinous
    Stability
    Fracture
    Conchoidal, Uneven
    Cleavage
    Poor, in two directions