Keshi Pearls Gemstone & Information | Gemopedia by JTV | Gemopedia™

Keshi Pearls

A happy accident of pearl farming, keshi pearls are produced by chance. Saltwater oysters sometimes reject their bead implant, but particles of the accompanying mantle tissue remain and stimulate the production of nacre in flat, petal-like shapes. They are often removed as seed pearls, inspiring their name, meaning "poppy seed" in Japanese. While some people think they should be considered natural pearls, they are a by-product of the culturing process so this is not technically correct. One of the most striking characteristics of South Sea keshi pearls is their very intense luster and iridescence, sometimes greater than seen in the finest cultured pearls.

Colors

Almost Any Color Usually White, Cream

  • Keshi-pearls classification

    CommonName
    Keshi Pearls
    Species
    NA
    Variety
    Keshi Pearls
    Colors
    Almost Any Color Usually White, Cream
    AlternateNames
    Chance Pearls
    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
    Keshi pearls are usually off round or baroque because they were formed from the mantle tissue from a rejected implantation. They are becoming rare in the market due to improved culturing techniques. Keshi pearls can be freshwater SG: 2.66 to 2.78 or Saltwater SG: 2.61 to 2.85.
  • Keshi-pearls chemistry & crystallography

    ChemicalName
    calcium carbonate + conchiolin and water
    ChemicalFormula
    CaCO3
    Synthesis
    CrystalSystem
    Orthorhombic
    ChemistryClassification
    Organic
    Nature
    Cultured
    Crystallinity
    ChemistryComments
  • Keshi-pearls optical properties

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

    Hardness
    2.5-4
    CharacteristicComments
    Streak
    SpecificGravity
    2.61-2.85
    Toughness
    Good
    Inclusions
    Keshi pearls have intense luster and iridescent surface.
    Luster
    Dull
    Stability
    Fair
    Fracture
    Uneven
    Cleavage
    None