Opal Doublet Gemstone & Information | Gemopedia by JTV | Gemopedia™

Opal Doublet

An opal doublet is an assembled gem that consists of a thin slice of natural opal attached to a second layer of material with a bonding agent. The types of materials used for opal doublets vary considerably but may include ironstone, sandstone, black plastic or quartz. Opal doublets often provide a more affordable alternative to solid opals and are often used today for mass-produced jewelry.

Colors

Variety Of Colors

  • Opal-doublet classification

    CommonName
    Opal Doublet
    Species
    Opal Doublet
    Variety
    Colors
    Variety Of Colors
    AlternateNames
    GemstoneGroups
    KeySeparations
    Appearance and magnification
    ClassificationComments
    The base of opal doublets can be made of potch opal, dyed black chalcedony, glass or other matrix materials.
  • Opal-doublet chemistry & crystallography

    ChemicalName
    ChemicalFormula
    SiO2-nH2O with base
    Synthesis
    assembled
    CrystalSystem
    NA
    ChemistryClassification
    Nature
    Composite
    Crystallinity
    ChemistryComments
  • Opal-doublet optical properties

    Transparency
    Semitranslucent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.45
    Tolerance:-0.25
    Birefringence
    OpticCharacter
    NA
    OpticSign
    PolariscopeReaction
    Singly Refractive (SR)
    Fluorescence
    SWUV:
    LWUV:
    CCFReaction
    Pleochroism
    None
  • Opal-doublet characteristic physical properties

    Hardness
    CharacteristicComments
    Streak
    SpecificGravity
    Toughness
    Inclusions
    Look for assembled nature and glue layer in opal doublets. Look for straight separation planes to distinguish opal doublets from natural opal that contain a potch opal under layer. These stones might have areas of potch or matrix that lack play-of-color. Synthetic opal will have a more uniform play-of-color appearance. Stones are sometimes glued using black cement to give the appearance of a black opal.
    Luster
    Vitreous
    Stability
    Fracture
    Cleavage
    None