Imperial Topaz Gemstone & Information | Gemopedia by JTV | Gemopedia™

Imperial Topaz

At the height of Imperial Russia's power, orange-pink topaz was brought from Brazil to decorate the jewelry of the Tzarina. Since then, these colors have been known as imperial topaz, and still today remains one of the most coveted topaz varieties. Interestingly enough, some sources dispute this legend and state that imperial topaz was indeed named in honor of the Brazilian ruler in power at the time, Emperor Don Pedro. Classified as a rare collector's gem, the world's supply of imperial topaz comes from sources in the Brazilian state of Minas Gerais. It is generally the reddish-orange or orange-red variety of topaz that's considered "imperial." Some also consider yellowish-orange, cognac-colored and pure orange to be imperial topaz.

Colors

Fine Medium Reddish Orange, Orange Red

  • Imperial-topaz classification

    CommonName
    Imperial Topaz
    Species
    Topaz
    Variety
    Imperial Topaz
    Colors
    Fine Medium Reddish Orange, Orange Red
    AlternateNames
    GemstoneGroups
    KeySeparations
    refractive index, birefringence, optic character; possibly specific gravity.
    ClassificationComments
    Biaxial positive common point is 0.001 from low RITopaz can have an RI of 1.619 to 1.627 (+0.010/-0.010).
  • Imperial-topaz chemistry & crystallography

    ChemicalName
    aluminium silicate fluoride hydroxide
    ChemicalFormula
    Al2(F,OH)2SiO4
    Synthesis
    CrystalSystem
    Orthorhombic
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Imperial-topaz optical properties

    Transparency
    Transparent
    Dispersion
    Strength: weak fire Value: 0.014
    OpticalComments
    RefractiveIndex
    1.629-1.637
    Birefringence
    0.008-0.01
    OpticCharacter
    Biaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: inert to weak greenish white
    LWUV: inert to moderate orange or yellow
    CCFReaction
    Pleochroism
    Dichroic, weak to moderate light red and orangy red to yellow
  • Imperial-topaz characteristic physical properties

    Hardness
    8
    CharacteristicComments
    Streak
    White
    SpecificGravity
    3.49-3.57 Typical:3.53
    Toughness
    Good
    Inclusions
    Imperial topaz is a type II clarity stone. Stones sometimes contain long tube-like cavities containing liquid, healed fractures and areas that look like they are starting to cleave. Stones might include 2-phase and 3-phase inclusions some of which contain more than one liquid that have not been mixed.
    Luster
    Vitreous
    Stability
    Fair
    Fracture
    Conchoidal
    Cleavage
    Perfect, in one direction