Freshwater Pearl Gemstone & Information | Gemopedia by JTV | Gemopedia™

Freshwater Pearl

Although freshwater pearl cultivation originated in Japan, China is now the world's major producer of freshwater pearls. The humble freshwater mussel, while not as widely celebrated as its cousin the oyster, is capable of producing high-quality pearls. Generally speaking, freshwater pearls tend not to have the luster and shine of saltwater, but do form in a variety of shapes and colors, and are typically sold at lower prices.

Colors

Gray, White, Cream, Yellow, Pink, Purple With Blue, Green Overtone, Orient

  • Freshwater-pearl classification

    CommonName
    Freshwater Pearl
    Species
    NA
    Variety
    Freshwater Pearl
    Colors
    Gray, White, Cream, Yellow, Pink, Purple With Blue, Green Overtone, Orient
    AlternateNames
    Kasumiga Pearl
    GemstoneGroups
    KeySeparations
    Appearance, RI, birefringence blink and magnification. A "tooth test" is commonly used in which a pearl is rubbed against a tooth; if gritty, this is an indication that the surface is nacre, versus plastic and glass imitations that feel smooth.
    ClassificationComments
    Typical size of freshwater pearls are 2 to 13mm. They are produced by the Hyriopsis schlegeli, Hyriopsis cumingli and Cristaria plicata mussels. Kasumiga pearls were farmed in the Japanese Lake Kassumigaura in the hybrid Hyriopsis schlegeli/ Hyriopsis cumingli mussel.
  • Freshwater-pearl chemistry & crystallography

    ChemicalName
    calcium carbonate + conchiolin and water
    ChemicalFormula
    CaCO3
    Synthesis
    CrystalSystem
    NA
    ChemistryClassification
    Organic
    Nature
    Cultured
    Crystallinity
    ChemistryComments
  • Freshwater-pearl optical properties

    Transparency
    Translucent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.53-1.685
    Birefringence
    0.155
    OpticCharacter
    NA
    OpticSign
    NA
    PolariscopeReaction
    Aggregate (AGG)
    Fluorescence
    SWUV: Variable
    LWUV: Variable
    CCFReaction
    Pleochroism
    None
  • Freshwater-pearl characteristic physical properties

    Hardness
    2.5-4
    CharacteristicComments
    Streak
    SpecificGravity
    2.72-2.78
    Toughness
    Good
    Inclusions
    If the pearl is drilled you can inspect the hole to look for lack of bead nucleus.
    Luster
    Dull
    Stability
    Poor
    Fracture
    Uneven
    Cleavage
    None