Iris Agate Gemstone & Information | Gemopedia by JTV | Gemopedia™

Iris Agate

A semitransparent to translucent member of the chalcedony species, iris agate is a phenomenal variety exhibiting an iridescent rainbow-like range of colors throughout the stone. It is highly prized by collectors and designers.

Colors

Colorless

  • Iris-agate classification

    CommonName
    Iris Agate
    Species
    Quartz
    Variety
    Chalcedony
    Colors
    Colorless
    AlternateNames
    GemstoneGroups
    KeySeparations
    RI, SG, appearance in transmitted light and fracture
    ClassificationComments
    Stones are usually cut in thin slices so iridescence can be seen in transmitted light
  • Iris-agate chemistry & crystallography

    ChemicalName
    silicon dioxide (aka silica)
    ChemicalFormula
    SiO2
    Synthesis
    CrystalSystem
    Trigonal
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Polycrystalline
    ChemistryComments
  • Iris-agate optical properties

    Transparency
    Semitransparent To Translucent
    Dispersion
    Strength: none
    OpticalComments
    RefractiveIndex
    1.535-1.539
    Birefringence
    0.004-0.004
    OpticCharacter
    Uniaxial
    OpticSign
    Positive
    PolariscopeReaction
    Aggregate (AGG)
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    None
  • Iris-agate characteristic physical properties

    Hardness
    6.5-7
    CharacteristicComments
    Streak
    SpecificGravity
    2.55-2.7 Typical: 2.6
    Toughness
    Excellent
    Inclusions
    Iris agate iridescence has a banded appearance.
    Luster
    Vitreous
    Stability
    Good
    Fracture
    Conchoidal
    Cleavage
    None