Magnesite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Magnesite

Magnesite, a member of the calcite mineral group, is often found in massive form as well-formed transparent crystals are rare. Pure magnesite crystals are colorless, and any impurities present affect color, which is typically light yellow to brown or gray. Magnesite has perfect cleavage in three directions, making faceting extremely difficult. Faceted gems are often found in private collections or museums.

Colors

White, Colorless, Yellowish, Brown, Gray, Any Color If Dyed

  • Magnesite classification

    CommonName
    Magnesite
    Species
    Magnesite
    Variety
    Colors
    White, Colorless, Yellowish, Brown, Gray, Any Color If Dyed
    AlternateNames
    GemstoneGroups
    Calcite
    KeySeparations
    Appearance, RI and birefringence blink.
    ClassificationComments
    Then opaque is commonly dyed to imitate lapis, turquoise or coral.
  • Magnesite chemistry & crystallography

    ChemicalName
    magnesium carbonate
    ChemicalFormula
    MgCO3
    Synthesis
    CrystalSystem
    Trigonal
    ChemistryClassification
    Carbonate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Magnesite optical properties

    Transparency
    Transparent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.509-1.7
    Birefringence
    0.191
    OpticCharacter
    Uniaxial
    OpticSign
    Negative
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert to moderate bluish white
    LWUV: Inert to moderate bluish white or yellowish white
    CCFReaction
    sometimes red if dyed
    Pleochroism
    Unobservable
  • Magnesite characteristic physical properties

    Hardness
    3.5-5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3-3.2
    Toughness
    Varies
    Inclusions
    Dye, gray veining.
    Luster
    Vitreous
    Stability
    Fracture
    Granular, Uneven
    Cleavage
    Perfect, in one direction