Jet Gemstone & Information | Gemopedia by JTV | Gemopedia™

Jet

Jet is generally classified as a lignite coal and has a high carbon content and a layered structure. It is typically black to dark brown and can sometimes contain tiny inclusions of pyrite. Jet has been carved for ornamental purposes since prehistoric times.

Colors

Very Dark Brown To Black

  • Jet classification

    CommonName
    Jet
    Species
    Jet
    Variety
    Colors
    Very Dark Brown To Black
    AlternateNames
    Whitby Jet
    GemstoneGroups
    KeySeparations
    RI and SG(low heft), hot point coal like smell. Stones have very low heft and will sometimes have a spot RI of 1.680.
    ClassificationComments
    Misnomer: black amber. Warm to touch. Becomes electrically charged when rubbed with wool. Jet will break rather than than curl when shaved.
  • Jet chemistry & crystallography

    ChemicalName
    hydrated hydro carbon
    ChemicalFormula
    C,H,O-2H2O
    Synthesis
    CrystalSystem
    NA
    ChemistryClassification
    Organic
    Nature
    Natural
    Crystallinity
    Non-Crystalline
    ChemistryComments
  • Jet optical properties

    Transparency
    Semitranslucent - Opaque
    Dispersion
    Strength: none
    OpticalComments
    RefractiveIndex
    1.66
    Tolerance:(+0.020/-0.020)
    Birefringence
    OpticCharacter
    NA
    OpticSign
    PolariscopeReaction
    Singly Refractive (SR)
    Fluorescence
    SWUV: inert
    LWUV: inert
    CCFReaction
    Pleochroism
    None
  • Jet characteristic physical properties

    Hardness
    2.5-4
    CharacteristicComments
    Streak
    Black-Brown
    SpecificGravity
    1.19-1.34 Typical:1.32
    Toughness
    Poor
    Inclusions
    In some Jet specimens the original wood structure can be seen.
    Luster
    Vitreous
    Stability
    Fracture
    Conchoidal
    Cleavage
    None