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

Scallop Pearls

A non-nacreous calcareous concretion, scallop pearls may form in any member of the scallop family. A very rare occurrence, such pearls are typically collected by fishermen as a result of harvesting the meat of the shellfish. They are found in the coastal waters of Central and North America, especially Baja California. Unlike other calcareous concretions, scallop pearls are a maroon to plum color and often form in oval, drop-like shapes.

Colors

Brown, Tan, Purple, Yellow, Orange Interior Color White, Root Beer Color

  • Scallop-pearls classification

    CommonName
    Scallop Pearls
    Species
    Pearl
    Variety
    Colors
    Brown, Tan, Purple, Yellow, Orange Interior Color White, Root Beer Color
    AlternateNames
    Lion's Paw Pearl, Digby Scallop 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
    Lion's paw pearls are produced by the lion's paw scallop Nodipecten subnodosus and can originate from the coast of Central America, Baja California and the inland Sea of Cortx in Mexico. Atlantic Sea Scallop (Placpecten magellanicus) produces the scallop pearls that come from Digby, Nova Scotia.Atlantic sea scallops are produced by the North Atlantic deep-sea scallop, Placopecten magellanicus; the Atlantic bay scallop, Argopecten irradians, and the Atlantic Lion's Paw, Nodipecten nodosus.
  • Scallop-pearls chemistry & crystallography

    ChemicalName
    calcium carbonate + conchiolin and water
    ChemicalFormula
    CaCO3
    Synthesis
    CrystalSystem
    NA
    ChemistryClassification
    Organic
    Nature
    Natural
    Crystallinity
    Aggregate
    ChemistryComments
  • Scallop-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
  • Scallop-pearls characteristic physical properties

    Hardness
    2.5-4.5
    CharacteristicComments
    Streak
    SpecificGravity
    2.61-2.85
    Toughness
    Good
    Inclusions
    Lion's paw pearls sometimes have platelets that display adventuresence. They have a fibrous structure that has a patchwork like appearance. Lion's paw pearls are brown, purple, yellow and orange with an interior color of white, purple or root beer colorDigby scallop pearls are white or pale tan in color and have a silvery sheen. The appearance has roughly circular patches with a radiating pattern caused by parallel calcite fibers.
    Luster
    Dull
    Stability
    Poor
    Fracture
    Uneven
    Cleavage
    None