Thulite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Thulite

Thulite is the translucent to opaque pink variety of zoisite, which is often mottled or streaked with gray or white quartz. The name thulite is derived from its discovery location, Norway, which was once called Thule. This gem is also called rosaline. Thulite is often cut en cabochon for jewelry manufacture or carved into ornaments.

Colors

Pink To Red, Often With Mottled, Streaked With Gray, White

  • Thulite classification

    CommonName
    Thulite
    Species
    Zoisite
    Variety
    Thulite
    Colors
    Pink To Red, Often With Mottled, Streaked With Gray, White
    AlternateNames
    Rosaline, Unionite
    GemstoneGroups
    Epidote
    KeySeparations
    refractive index, appearance and SG
    ClassificationComments
    National gemstone of Norway. RI might be as low as mid 1.50s due to impurities
  • Thulite chemistry & crystallography

    ChemicalName
    calcium aluminum silicate hydroxide
    ChemicalFormula
    Ca2Al3(SiO4)3(OH)
    Synthesis
    CrystalSystem
    Orthorhombic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Thulite optical properties

    Transparency
    Translucent - Opaque
    Dispersion
    Strength: weak fire Value: 0.021
    OpticalComments
    RefractiveIndex
    1.691-1.7
    Tolerance:(+0.005/-0.005)
    Birefringence
    0.008-0.013
    OpticCharacter
    Biaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    Unobservable
  • Thulite characteristic physical properties

    Hardness
    6-7
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3.1-3.45 Typical:3.35
    Toughness
    Varies
    Inclusions
    Thulite has white veining is due to calcite and the pink color is due to manganese.
    Luster
    Vitreous
    Stability
    Good
    Fracture
    Conchoidal, Uneven
    Cleavage
    Perfect, in one direction, Good, in one direction