Pargasite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Pargasite

Pargasite mostly occurs in a brown color, but has been found in greenish-brown to dark green and black. This gemstone was first found in Finland in 1814 and is named for its site of discovery. A member of the amphibole group, pargasite is closely related to hornblende. Some fine specimens of this rare gemstone have been faceted.

Colors

Bluish Green, Emerald Green, Greenish Brown Brown, Light Brown, Black

  • Pargasite classification

    CommonName
    Pargasite
    Species
    Pargasite
    Variety
    Colors
    Bluish Green, Emerald Green, Greenish Brown Brown, Light Brown, Black
    AlternateNames
    Pargasitic Hornblende
    GemstoneGroups
    Amphibole
    KeySeparations
    RI, birefringence
    ClassificationComments
  • Pargasite chemistry & crystallography

    ChemicalName
    ChemicalFormula
    NaCa2(Mg4Al)Si6Al2O22(OH)2
    Synthesis
    CrystalSystem
    Monoclinic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Pargasite optical properties

    Transparency
    Transparent - Translucent
    Dispersion
    Strength: weak fire
    OpticalComments
    RefractiveIndex
    1.613-1.663
    Birefringence
    0.02-0.024
    OpticCharacter
    Biaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    Trichroic, (in brown gems) moderate to strong colorless, yellow, and brown; (in green gems) moderate to strong greenish yellow, green, and greenish blue
  • Pargasite characteristic physical properties

    Hardness
    5-6
    CharacteristicComments
    Streak
    SpecificGravity
    3.04-3.26
    Toughness
    Poor
    Inclusions
    Luster
    Vitreous
    Stability
    Fracture
    Uneven
    Cleavage
    Perfect, in one direction