Bastnaesite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Bastnaesite

A rare gem, bastnaesite is named after the Swedish locality where it was originally discovered in 1841, the Bastnas mines. Color can range from honey yellow to reddish brown and crystals vary from transparent to translucent in appearance. Valued by industry as a source of rare-earth elements, bastnaesite is rare, but has been found in small quantities throughout the world. It is difficult to cut because it is a relatively soft mineral, however, its high refractive index, combined with its rarity, make it an exciting gem to own.

Colors

Orange Brown, Brown, Yellow, Orangish Yellow

  • Bastnaesite classification

    CommonName
    Bastnaesite
    Species
    Bastnaesite
    Variety
    Colors
    Orange Brown, Brown, Yellow, Orangish Yellow
    AlternateNames
    BastnSite
    GemstoneGroups
    KeySeparations
    RI and birefringence
    ClassificationComments
    Strongly piezoelectric: development of opposite charges at the ends of the crystal when placed under stress.
  • Bastnaesite chemistry & crystallography

    ChemicalName
    cerium carbonate fluoride
    ChemicalFormula
    (Ce,La)(CO3)F
    Synthesis
    CrystalSystem
    Hexagonal
    ChemistryClassification
    Carbonate
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Bastnaesite optical properties

    Transparency
    Transparent
    Dispersion
    Strength: none
    OpticalComments
    RefractiveIndex
    Over the Limit 1.717-1.823
    Birefringence
    0.1
    OpticCharacter
    Uniaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV:
    LWUV:
    CCFReaction
    Pleochroism
    Unobservable
  • Bastnaesite characteristic physical properties

    Hardness
    4-4.5
    CharacteristicComments
    Streak
    SpecificGravity
    4.78-5.2
    Toughness
    Poor
    Inclusions
    Luster
    Vitreous
    Stability
    Poor
    Fracture
    Uneven
    Cleavage
    Poor, in one direction