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

Conch Pearl

A conch is a marine gastropod or, more simply, a large sea snail. Conchs are valued for their meat, shell and non-nacreous pearls. Conch pearls are formed by concentric layers of fibrous calcium. This layering often produces a much-desired flame structure, which is characteristic of conch pearls. Because they are a calcareous concretion, the pearls have a porcelain finish and luster, very similar to the interior of the conch shell. Conch pearls are not cultured, but are usually found as a by-product as fishermen clean their catch for conch meat. The gems are usually baroque or oval in shape and generally a salmon-colored orange-pink.

Colors

Beige, Ivory, White, Brown, Mottled Coloring Pink, Yellow, Orange, Red

  • Conch-pearl classification

    CommonName
    Conch Pearl
    Species
    NA
    Variety
    Conch Pearl
    Colors
    Beige, Ivory, White, Brown, Mottled Coloring Pink, Yellow, Orange, Red
    AlternateNames
    GemstoneGroups
    KeySeparations
    RI, birefringence blink, magnification and appearance
    ClassificationComments
    Use birefringence blink method to obtain birefringence. Misnomer: Nassau pearls. Conch pearls are not considered true pearls. They come from the giant conch Strombus gigas. Color may fade if pearl is exposed to sunlight for long periods of time.
  • Conch-pearl chemistry & crystallography

    ChemicalName
    calcium carbonate, conchiolin and water
    ChemicalFormula
    CaCO3 with H2O and other organic materials
    Synthesis
    CrystalSystem
    NA
    ChemistryClassification
    Carbonate
    Nature
    Natural
    Crystallinity
    Non-Crystalline
    ChemistryComments
  • Conch-pearl optical properties

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

    Hardness
    2.5-4
    CharacteristicComments
    Streak
    SpecificGravity
    2.83-2.87 Typical:2.85
    Toughness
    Fair
    Inclusions
    Conch pearls have a flame like structure and does not have nacre but a porcelain like finish.
    Luster
    Dull
    Stability
    Poor
    Fracture
    Uneven
    Cleavage
    None