Carnelian Gemstone & Information | Gemopedia by JTV | Gemopedia™

Carnelian

Carnelian is a translucent orange to red variety of chalcedony. Uniformly colored cryptocrystalline quartz, its red tints are caused by traces of iron oxide. The name is derived from the Latin world for flesh, carne, due to its orangey red color. Carnelian has been appreciated since antiquity, and is one of the first known materials ever to be used as a gemstone.

Colors

Orangy Red To Brownish Red To Brownish Orange

  • Carnelian classification

    CommonName
    Carnelian
    Species
    Quartz
    Variety
    Chalcedony
    Colors
    Orangy Red To Brownish Red To Brownish Orange
    AlternateNames
    Cornelian
    GemstoneGroups
    KeySeparations
    RI, SG, appearance and fracture.
    ClassificationComments
    Color is key to its designation. Lighter and more saturated than sard. Iron is the coloring agent.
  • Carnelian chemistry & crystallography

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

    Transparency
    Semitransparent - 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
  • Carnelian characteristic physical properties

    Hardness
    6.5-7
    CharacteristicComments
    Streak
    SpecificGravity
    2.55-2.7 Typical:2.6
    Toughness
    Excellent
    Inclusions
    Carnelian sometimes has a cloudy appearance. If stripes are seen through transmitted light then it is dyed agate.
    Luster
    Vitreous
    Stability
    Good
    Fracture
    Conchoidal, Granular
    Cleavage
    None