Thomsonite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Thomsonite

Named for Thomas Thomson, a Scottish chemist, thomsonite is a mineral in the zeolite group. Ranging from translucent to opaque in appearance, it is found in various colors including brown, yellow, orange, pink, green, white and gray. Most famous for its nodular aggregates that exhibit a radial pattern, thomsonite may be found in various global locations, including Canada, the Czech Republic, Germany, Greenland, Scotland and the United States.

Colors

Brown, Yellow, Orange, Pink, Green, White, Gray

  • Thomsonite classification

    CommonName
    Thomsonite
    Species
    Thomsonite
    Variety
    Colors
    Brown, Yellow, Orange, Pink, Green, White, Gray
    AlternateNames
    Gibsonite, Lintonite, Ozarkite
    GemstoneGroups
    KeySeparations
    ClassificationComments
    Gibsonite is the fibrous pink version of thomsonite from Scotland. Lintonite is the translucent green variety of thomsonite for the Lake Superior region. Ozarkite is the white variety of thomsonite from the Magnet Cove region of Arkansas. Misnomer: Lake Superior agate
  • Thomsonite chemistry & crystallography

    ChemicalName
    ChemicalFormula
    NaCa2Al5Si5O20-6H2O
    Synthesis
    CrystalSystem
    Orthorhombic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Polycrystalline
    ChemistryComments
  • Thomsonite optical properties

    Transparency
    Translucent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.515-1.54
    Tolerance:(+0.015/-0.018)
    Birefringence
    0.025
    OpticCharacter
    Biaxial
    OpticSign
    Positive
    PolariscopeReaction
    Aggregate (AGG)
    Fluorescence
    SWUV: Inert
    LWUV: Inert to weak white
    CCFReaction
    Pleochroism
    Unobservable
  • Thomsonite characteristic physical properties

    Hardness
    5-5.5
    CharacteristicComments
    Streak
    SpecificGravity
    2.2-2.4 Typical:2.35
    Toughness
    Fair
    Inclusions
    Thomsonite has a radial fibrous structure that gives an eye ball like appearance and looks similar to agate.
    Luster
    Vitreous
    Stability
    Fracture
    Uneven
    Cleavage
    Perfect, in one direction