Gahnospinel Gemstone & Information | Gemopedia by JTV | Gemopedia™

Gahnospinel

Gahnospinel is the rare violetish to dark blue, zinc-rich variety of spinel. A variety of spinel rich in zinc, much of the world's supply of gahnospinel comes from Sri Lanka. Since gahnospinel is chemically midway between spinel and gahnite, hence its name is a combination of the two. The first half is in honor of Johann Gottlieb Gahn, a Swedish chemist and mineralogist.

Colors

Green, Blue Dark In Tone, Very Dark Green, Brown To Black

  • Gahnospinel classification

    CommonName
    Gahnospinel
    Species
    Gahnospinel
    Variety
    Colors
    Green, Blue Dark In Tone, Very Dark Green, Brown To Black
    AlternateNames
    GemstoneGroups
    Spinel
    KeySeparations
    Dark color, RI, SR nature, spectrum and SG
    ClassificationComments
    Gahnospinel is rich in zinc and has properties in between spinel and gahnite.
  • Gahnospinel chemistry & crystallography

    ChemicalName
    magnesium zinc aluminum oxide
    ChemicalFormula
    MgAl2O4 and ZnAl2O4
    Synthesis
    CrystalSystem
    Cubic
    ChemistryClassification
    Oxide
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Gahnospinel optical properties

    Transparency
    Transparent - Translucent
    Dispersion
    OpticalComments
    RefractiveIndex
    1.76
    Tolerance:(+0.020/-0.020)
    Birefringence
    OpticCharacter
    NA
    OpticSign
    PolariscopeReaction
    Singly Refractive (SR)
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    None
  • Gahnospinel characteristic physical properties

    Hardness
    7.5-8
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3.61-4.41 Typical:4.01
    Toughness
    Good
    Inclusions
    Luster
    Vitreous
    Stability
    Fracture
    Conchoidal
    Cleavage
    None