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

Iris Quartz

This unique variety of quartz displays phenomenal iridescence. Its beautiful rainbow of color is caused by reflection and refraction of light within the tiny parallel crystal layers within its structure. Fittingly, it is also called "aurora quartz," "iridescent quartz" or "rainbow quartz."

Colors

Colorless, Slightly Purple, Yellow Displaying Internal Spectral Colors

  • Iris-quartz classification

    CommonName
    Iris Quartz
    Species
    Quartz
    Variety
    Iris Quartz
    Colors
    Colorless, Slightly Purple, Yellow Displaying Internal Spectral Colors
    AlternateNames
        Rainbow Quartz
    GemstoneGroups
    KeySeparations
    Refractive index, appearance, birefringence, optic character and optic figure. A bull's-eye optic figure is determinative for quartz; may also show Airy's spiral optic figure and Brazil-law twinning under crossed polarizing filters.
    ClassificationComments
    This interference phenomenon in iris quartz is due to reflection and refraction on extremely thin parallel brazil-law twinning lamellae. The rainbow quartz name used for other types of quartz, including those showing internal interference colors caused by fractures ("crack rainbows"), and interference colors caused by superficial thin films of limonite or other minerals.
  • Iris-quartz chemistry & crystallography

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

    Transparency
    Transparent - Translucent
    Dispersion
    Strength: weak fire Value: 0.013
    OpticalComments
    RefractiveIndex
    1.544-1.553
    Tolerance:very constant
    Birefringence
    0.009
    OpticCharacter
    Uniaxial
    OpticSign
    Positive
    PolariscopeReaction
    Singly Refractive (SR) With ADR
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    None
  • Iris-quartz characteristic physical properties

    Hardness
    7
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.64-2.69 Typical:2.66
    Toughness
    Good
    Inclusions
    Iris quartz may contain liquid, two-phase and three-phase inclusions, negative crystals, minerals, needles, rutile and iron particles.
    Luster
    Vitreous
    Stability
    Good
    Fracture
    Conchoidal
    Cleavage
    None