Microcline Feldspar Gemstone & Information | Gemopedia by JTV | Gemopedia™

Microcline Feldspar

Microcline is one of the most common feldspar minerals. It is used in ceramics and is in deep seated, felsic rocks like granite, granodiorite, and syenite. Blue-green specimens of microcline are called amazonstone or amazonite and are used in jewelry, generally cut into cabochons. Its name refers to the small incline seen in its crystal structure.

Colors

White, Light Orange To Pink

  • Microcline-feldspar classification

    CommonName
    Microcline Feldspar
    Species
    Microcline
    Variety
    Colors
    White, Light Orange To Pink
    AlternateNames
    GemstoneGroups
    Feldspar
    KeySeparations
    appearance, RI, magnification, SG, possible fluorescence
    ClassificationComments
    Green variety is amazonite
  • Microcline-feldspar chemistry & crystallography

    ChemicalName
    potassium aluminum silicate
    ChemicalFormula
    KAlSi3O8
    Synthesis
    CrystalSystem
    Triclinic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Aggregate
    ChemistryComments
  • Microcline-feldspar optical properties

    Transparency
    Semitranslucent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.522-1.53
    Tolerance:(+0.004/-0.004)
    Birefringence
    0.008
    OpticCharacter
    Biaxial
    OpticSign
    Negative
    PolariscopeReaction
    Fluorescence
    SWUV: inert
    LWUV: weak yellowish green
    CCFReaction
    Pleochroism
    Unobservable
  • Microcline-feldspar characteristic physical properties

    Hardness
    6-6.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.54-2.58 Typical:2.56
    Toughness
    Poor
    Inclusions
    Mottled coloring with grid like white streaks or patterns caused by cleavage.
    Luster
    Vitreous
    Stability
    Fracture
    Uneven, Splintery
    Cleavage
    Perfect, in two directions