Sugilite Gemstone & Information | Gemopedia by JTV | Gemopedia™

Sugilite

Sugilite belongs to a class of minerals known as silicates and is a member of the milarite group. A relatively recent addition to the realm of gemstones, sugilite was discovered in 1944 by a Japanese geologist, Ken-ichi Sugi. The mineral is named in his honor. The original find was a yellowish brown variety that was of no interest to the jewelry industry. It was not until 1979 that the first massive aggregates, exhibiting a rich purple color, were discovered in a South African manganese mine. This material was attractive and gained the attention of the gemstone industry. It is predominantly found in the form of cabochons of various shapes and sizes, but has also been used as a component in intarsia jewelry. It is sometimes carved into decorative objects and fashioned into beads.

Colors

Red-Purple To Bluish Purple, Rarely Pink

  • Sugilite classification

    CommonName
    Sugilite
    Species
    Sugilite
    Variety
    Colors
    Red-Purple To Bluish Purple, Rarely Pink
    AlternateNames
    Royal Azel, Royal Lavulite
    GemstoneGroups
    KeySeparations
    Intense purplish color, RI, spectrum and SG
    ClassificationComments
    Might show RI of 1.54 due to quartz impurities Misnomer: purple turquoise
  • Sugilite chemistry & crystallography

    ChemicalName
    potassium sodium lithium iron manganese silicate
    ChemicalFormula
    (K,NA)(Na,Fe)2(Li2Fe)Si12O30
    Synthesis
    CrystalSystem
    Hexagonal
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline to Aggregate
    ChemistryComments
  • Sugilite optical properties

    Transparency
    Semitransparent - Opaque
    Dispersion
    OpticalComments
    RefractiveIndex
    1.607-1.61
    Tolerance:(+0.001/-0.002)
    Birefringence
    0.003
    OpticCharacter
    Uniaxial
    OpticSign
    Negative
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    Pleochroism
    None
  • Sugilite characteristic physical properties

    Hardness
    5.5-6.5
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.69-2.79 Typical:2.74
    Toughness
    Good
    Inclusions
    Sugilite might have banded appearance.
    Luster
    Vitreous
    Stability
    Fracture
    Granular
    Cleavage
    None