Tanzanite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Tanzanite

Henry Platt, former president of Tiffany & Co., described tanzanite's discovery in 1967 as THE most important gemstone find in 2000 years! This single 5-mile strip of land in Tanzania remains the only commercially viable source of this stone that has become one of the world's most sought-after and admired gems. Tanzanite is a relatively new gemstone in the world of gemology and jewelry, and though its history is brief, it is no less illustrious than many ancient gems. Tanzanite is a single-source gemstone that is a thousand times rarer than diamond, and is only gaining popularity.

Colors

Blue, Violetish Blue To Violet, Bluish Purple

  • Tanzanite classification

    CommonName
    Tanzanite
    Species
    Zoisite
    Variety
    Tanzanite
    Colors
    Blue, Violetish Blue To Violet, Bluish Purple
    AlternateNames
    GemstoneGroups
    Epidote
    KeySeparations
    refractive index, birefringence, optic character and pleochroism
    ClassificationComments
    Crystal habit is typically an orthorhombic prism with a roughly rectangular cross-section and striations parallel to the c axis on some faces. The zoisite species also occurs in pink, yellow, green and brown varieties. Misnomer: Meru sapphire, 24th Wedding anniversary
  • Tanzanite chemistry & crystallography

    ChemicalName
    calcium aluminum silicate with hydroxyl (OH)
    ChemicalFormula
    Ca2Al3(SiO4)3(OH)
    Synthesis
    CrystalSystem
    Orthorhombic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Tanzanite optical properties

    Transparency
    Transparent - Translucent
    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
    Trichroic, (in unheated gems) strong blue, purplish red and greenish yellow; (in heated gems) strong blue, slightly lighter blue, and purple
  • Tanzanite characteristic physical properties

    Hardness
    6.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3.1-3.45 Range:0.1/-0.25 Typical:3.35
    Toughness
    Varies
    Inclusions
    Tanzanite is a type I clarity stone. Stones rarely contain needles, chromite inclusions, growth and etch tubes.
    Luster
    Vitreous
    Stability
    Good
    Fracture
    Conchoidal, Uneven
    Cleavage
    Perfect, in one direction, Good, in one direction