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

Tridacna Pearls

Tridacna pearls form within the tridacna clam, commonly known as the "giant clam." These large mollusks grow in the warm coral reefs of the Indo-Pacific Ocean, living up to 100 years and reaching sizes of up to 47 inches across. Understandably, the largest pearl of any kind on record is a tridacna pearl weighing 6.4 kilograms. These non-nacreous pearls have a porcelain-like white surface.

Colors

Yellowish White

  • Tridacna-pearls classification

    CommonName
    Tridacna Pearls
    Species
    NA
    Variety
    Tridacna Pearls
    Colors
    Yellowish White
    AlternateNames
    GemstoneGroups
    KeySeparations
    RI, birefringence blink, magnification and appearance.
    ClassificationComments
    Use birefringence blink method to obtain birefringence. Tridacna pearls are not a true pearls, they come from the giant clam. They range in size from 1 cm to very large. Misnomer: coconut pearl.
  • Tridacna-pearls chemistry & crystallography

    ChemicalName
    calcium carbonate, conchiolin and water
    ChemicalFormula
    CaCO3 with H2O and other organic materials
    Synthesis
    CrystalSystem
    NA
    ChemistryClassification
    Carbonate
    Nature
    Natural
    Crystallinity
    Aggregate
    ChemistryComments
  • Tridacna-pearls optical properties

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

    Hardness
    2.5-4
    CharacteristicComments
    Streak
    SpecificGravity
    2.83-2.87 Typical: 2.85
    Toughness
    Fair
    Inclusions
    Tridacna pearls have a yellow to white porcelain appearance with flame like structure.
    Luster
    Dull
    Stability
    Poor
    Fracture
    Uneven
    Cleavage
    None