Topaz Information: Much More Than a Blue Gemstones

December 10, 2016

Topaz Gemstone Buying Guide

The etymologic history of the word topaz is uncertain.
The Roman writer Pliny suggested in the first century AD that the name derived from the Greek word “Topazos" an island in the Red Sea.
Another theory is that the name derives from the Sanskrit word "pita" meaning fire, referring to the yellow color of some topaz.

 

Contens

  1. Topaz Color
  2. Price of Topaz
  3. Cut and Sizes of Topaz
  4. Topaz Clarity
  5. Where is Topaz Found, genesis and origin
  6. November Birthstone, Topaz
  7. Enhancements and Synthesis
  8. General Description Physical and Optical Properties of Topaz

 

TOPAZ COLOR

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The most common color of the topaz is colorless and brown, not blue. The color blue, mostly, is caused by treatment.
On the nature found colorless (white), brown, blue, yellow, orange, pink, purple and red topaz.
Topaz is allochromatic, its color is caused by impurity elements or color centers (crystallographic defects).

 

  • Colorless Topaz or White Topaz
  • Blue or Green Topaz – Color centers
  • Yellow or Brown Topaz – Color centers
  • Pink or Red Topaz colored by Cr
  • Orange Topaz colored by Cr and color center
  • Peach Orange Topaz

     

    PRICE OF TOPAZ

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    The most expensive color topaz are rich Pink or Red Topaz, followed by rich Orange Topaz. These vivid colors (red, pink, and orange) can cost excess of $1500/ct in contrast with the blue topaz (commonly treated) that is available by not more of $60/ct. Blue Topaz is affordable gemstone.

    White or Colorless Topaz is an affordable gemstone. It's ideal for jewelry, its hardness (8 Mohs Scale), transparency, brilliance and its low price, make this white gemstone an affordable choice for your jewels.

     

     

    CUT & SIZES OF TOPAZ

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    blue topaz fancy cut

    Due to the prismatic habit of the crystals, topaz is often cut into elongated shapes (rectangular, emerald, oval, pear, teardrop).

     

    Blue topaz is cut into any style and size.

     

    Blue Topaz is available in large sizes, however Red and Pink Topaz are common small sizes.


     

     

    TOPAZ CLARITY

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    Topaz will show eye-clean inclusion, except Red and Pink Topaz will show more inclusions.

     

    Typical inclusions 

    Biphasic and Triphasic inclusions with immiscible liquids, veils, fingerprints or feathers. Solid inclusions (hematite, fluorite, etc). Solid inclusions finished “comet tail”. Needle-like rutile inclusion. Straight lines of growth.

    Inclusions in Topaz

     

     

    WHERE IS TOPAZ FOUND - GENESIS & ORIGIN

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    Genesis 

    Topaz occurs most commonly in pegmatites, granites and rhyolites (igneous rocks). Also it is found in secondary deposits (alluvial).

    Topaz is found

    Afghanistan, Brazil (Ouro Preto–Minas Gerais), Burma (Myanmar), Canada, China, Kazakhastan, India, Madagascar, Mozambique, Namibia, Pakistan, Russia, Sri Lanka, Tajikistan, Ukraine, USA, Vietnam, Zimbabwe…

    White Topaz Cushion Cut 11.13 carat

     

    NOVEMBER BIRTHSTONES TOPAZ

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    Topaz and Citrine are the birthstones for November. The Blue Topaz is the gem gifted for 4th wedding anniversaries, and the Imperial Topaz is gifted for those celebrating their 23rd anniversary.

    More information about Birthstones.

     

    Topaz Lore & Legend

    Make us stronger, restore the soul, dispel anger, break spells, remove insomnia, longer life, are some of the legends that have been attributed to the topaz for centuries.

     

    blue topaz gems

    ENHANCEMENTS AND SYNTHESIS

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    Enhancements

    Irradiation + heat treatment: Colorless topaz is irradiated, brown topaz are obtained. This brown topaz is subjected to a thermal treatment that removes the brown component, obtaining blue topaz. This blue color  is stable to light.

    Irradiation: Colorless topaz is irradiated turning it brown topaz, the color is unstable (exposure to sunlight).

    Heat Treatment: Orange-brown topaz is treated to turning it Pink - Purple Topaz. (Natural pink topaz is rare)

    Coating: It consists of a thin layer deposition (microns) on the topaz. This deposition may be a dye to impart color or change its color.

    Also can be the deposition of a metallic material so that we get an iridescent topaz.

    This topaz is known by the name "Mystic Topaz" - "Rainbow Topaz". This thin layer is delicate, is easily scratched. Coating is not permanent.

     

    Synthesis

    Non-commercial

    Imitations

    Citrine, Smoky Quarz, Glass

     

    GENERAL DESCRIPTION PHYSICAL & OPTICAL PROPERTIES OF TOPAZ

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    Two-phase inclusions in orange topaz

    Two-phase inclusions

    Solid inclusions with comet tail in orange topaz

    Solid inclusions with "comet tail"

    Inclusions in peach orange topaz, detachment zone probably due to internal tensions

    Detachment zone probably due
    to internal tensions.
    NESOSILICATES

    Aluminium silicate that contains fluorine and hydroxyl. Al2 (F,OH)2 SiO4

    • Crystal system: Orthorhombic.
    • Habit: Combinations of rhombic prisms ( 4 sides) + rhombic dipyramids (8 sides) (sometimes + pinacoidal). It is very typical basal cleavage. Sometimes topaz prisms have vertical streaks.
    • Hardness (Mohs): 8
    • Fracture: Conchoidal, Irregular.
    • Transparency: Transparent, translucent.
    • Streak: White.
    • Lustre: Vitreous
    • Cleavage: Perfect
    • Dispersion: 0,014
    • Density: 3.49 – 3.57 g/cm3
    • Optic nature: Biaxial positive
    • Refractive index: 1.606 – 1.644
    • Birefringence: 0.008 to 0.011
    • Pleochroism: Weak to Moderate
    • Fluorescence: Mostly inert or weak.
    • Absorption spectrum: Not generally observable


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