Calcite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Calcite

Named for its calcium content, calcite is one of Earth's more abundant minerals-- you've probably seen it many times and not known exactly what it was. It is found in granite and limestone veins and streaks as well as other rocks used in driveways and roads. Gem-quality calcite, however, takes on a quite different look. You may have seen colorless calcite crystals used as examples for double image refraction, but it also forms as white, gray, yellow, pink and green gems. Material is often faceted or polished en cabochon, or carved into ornamental objects.

Colors

White, Yellowish, Pink, Orange, Colorless, Any Color If Dyed

  • Calcite classification

    CommonName
    Calcite
    Species
    Calcite
    Variety
    Colors
    White, Yellowish, Pink, Orange, Colorless, Any Color If Dyed
    AlternateNames
    Limespar
    GemstoneGroups
    Calcite
    KeySeparations
    RI, birefringence, SG, eye visible doubling, cleavage and appearance. Use birefringence blink method.
    ClassificationComments
    Might be thermoluminescent phosphoresce upon heating or triboluminescent luminescence caused by friction.
  • Calcite chemistry & crystallography

    ChemicalName
    calcium carbonate
    ChemicalFormula
    CaCO3
    Synthesis
    CrystalSystem
    Trigonal
    ChemistryClassification
    Carbonate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Calcite optical properties

    Transparency
    Transparent - Opaque
    Dispersion
    Strength: moderate fire Value: 0.17
    OpticalComments
    RefractiveIndex
    1.486-1.658
    Birefringence
    0.172
    OpticCharacter
    Uniaxial
    OpticSign
    Negative
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Variable
    LWUV: Variable
    CCFReaction
    Pleochroism
    None
  • Calcite characteristic physical properties

    Hardness
    3
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.65-2.75 Typical:2.7
    Toughness
    Varies
    Inclusions
    Look for dye concentrations in dyed calcite material.
    Luster
    Vitreous
    Stability
    Poor
    Fracture
    Conchoidal, Granular, Splintery
    Cleavage
    Perfect, in three directions