Howlite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Howlite

Not well known to the general public, howlite is one of those minerals that is almost more famous for imitating another mineral. In this case, the other mineral is turquoise, a phosphate gemstone. Howlite is naturally milky white in color and often has dark vein-like mineral inclusions. Because of its porosity, it accepts dye fairly easily, achieving a turquoise-like blue color. Howlite accepts a nice polish and its porcelain-like luster is appealing.

Colors

White, Often With Dark Gray, Black Spider Web Matrix; Commonly Dyed Most Often To Imitate Turquoise, Lapis, Coral, Rhodonite

  • Howlite classification

    CommonName
    Howlite
    Species
    Howlite
    Variety
    Colors
    White, Often With Dark Gray, Black Spider Web Matrix; Commonly Dyed Most Often To Imitate Turquoise, Lapis, Coral, Rhodonite
    AlternateNames
    Howlithe, Turquenite, Dyed Howlite
    GemstoneGroups
    KeySeparations
    appearance, RI, SW fluorescence and SG
    ClassificationComments
  • Howlite chemistry & crystallography

    ChemicalName
    ChemicalFormula
    Ca2B5SiO9(OH)5
    Synthesis
    CrystalSystem
    Monoclinic
    ChemistryClassification
    Borate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Howlite optical properties

    Transparency
    Semitranslucent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.586-1.605
    Tolerance:(+0.003/-0.003)
    Birefringence
    0.019
    OpticCharacter
    Biaxial
    OpticSign
    Negative
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: inert to weak bluish white or orange
    LWUV: Inert to moderate bluish white or orange
    CCFReaction
    Dyed blue: pink to red
    Pleochroism
    None
  • Howlite characteristic physical properties

    Hardness
    3-3.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.45-2.71 Typical:2.58
    Toughness
    Varies
    Inclusions
    Howlite is often dyed to look like turquoise or lapis lazuli. The stones frequently have a dark gray or black spider web matrix.
    Luster
    Vitreous
    Stability
    Poor
    Fracture
    Granular
    Cleavage
    None