search
  • Iscriviti
    Registrati
  • Solo per i clienti di lingua inglese

    Gratuito - Solo USA e Canada:
    1-800-464-1640

    Internazionale:
    +66-39303404

  • Change Language
  • USD

About Green Zircon, Low Zircon & Metamict Zircon

Zircon is an unusual gemstone on a number of counts. Often confused with cubic zirconia, a made-made synthetic diamond substitute, natural zircon is actually the oldest mineral on Earth. In fact, according to samples found in Australia, researchers discovered that the material dates back from more than 4.4 billion years ago, even older than the moon itself. Zircon is of such important interest to geoscientists, it has spawned its own discipline known as 'zirconology'.

Another unusual thing about zircon is that its gemological properties exhibit very wide ranges. For example, if you look at zircon's values for hardness, specific gravity (density) and refractive index, you'll notice that the ranges are very wide. Gemological resources list zircon as having a hardness of 6.5 to 7.5; a density of 3.93 to 4.73; and a refractive index of 1.810 to 2.024.

The reason for the wide variation is that there is so-called low zircon and high zircon, with the high zircon having values at the top of the range. Low zircon - that with lower density, hardness and refractive index - forms as a result of a unique process associated with the presence of uranium and thorium. The natural radioactivity of these elements disrupts the crystal structure, thus causing changes in color and density. These changes take place over a long period of time through a process known as metamictization.

This so-called metamict zircon is always green or brown in color. Though externally it looks much like normal zircon, internally it has lost its crystal structure and has become isotropic glass. Though the metamictization process lowers a mineral's refractive index, hardness and specific gravity, it does not, curiously, affect the mineral's brilliance, dispersion or fire.

The green metamict zircon is quite rare and is prized by collectors. Some samples still emit low levels of radiation. The loss of crystal structure often makes the metamict specimens darker and cloudier, and some samples may be heated to lighten the color. Experiments have shown that prolonged heating can result in substantial recrystallization. Of all the many different varieties of colored stones available today, zircon is prized for its remarkable brilliance and fire.

Sri Lanka is the best known source for green metamict zircon, although low zircon specimens are also found in Burma, and may also exist in other well-known zircon deposits located throughout Cambodia. Cambodia and Southeast Asia are the important sources for fine zircon today, particularly when it comes to material suitable for the making of heat-treated blue zircon, which has become one of the most popular blue gemstones choices over recent years.

  • Prima Pubblicazione: November-13-2009
  • Ultima modifica: August-21-2017
  • © 2005-2021 GemSelect.com Tutti i diritti riservati.
    Qualsiasi riproduzione (testi o immagini) è strettamente proibita senza esplicita autorizzazione scritta da parte di GemSelect.com (SETT Company Ltd.).
More Shapes
Le pietre più conosciute
  • Zaffiro
  • Smeraldo
  • Rubino
  • Acquamarina
  • Zircone
  • Opale
  • Topazio
  • Tormalina
  • Granato
  • Ametista
  • Citrino
  • Tanzanite
Tutte le pietre preziose (139)
A B C D E F G H I K L M N O P Q R S T V Z
  • Acquamarina
  • Acquamarina effetto occhio di gatto
  • Agata
  • Agata dendritica
  • Agata di fuoco
  • Amazzonite
  • Ametista
  • Ametrine
  • Ammolite
  • Andalusite
  • Andesina Labradorite
  • Apatite
  • Apatite effetto occhio di gatto
  • Avventurina
  • Azzurrite druzy
  • Berillo
  • Berillo dorato
  • Calcedonio
  • Cat's Eye Opal
  • Charoite
  • Cianite
  • Citrino
  • Corallo
  • Corallo fossile
  • Cornerupina
  • Corniola
  • Crisoberillo
  • Crisocolla
  • Crisoprasio
  • Cromo diopside
  • Diamante
  • Diaspro
  • Diaspro cangiante
  • Diopside stellato
  • Druse emimorfite
  • Druzy Amethyst
  • Eliolite
  • Eliolite o pietra del sole
  • Eliolite o pietra del sole stellata
  • Ematite
  • Ematite o pietra del sangue
  • Enstatite
  • Fluorite
  • Fluorite che cambia colore
  • Gemme gatteggianti
  • Giada
  • Giadeite
  • Granato
  • Granato Malaya
  • Granato almandino
  • Granato cangiante
  • Granato del Mali
  • Granato demantoide
  • Granato di rodolite
  • Granato essonite
  • Granato grossularia
  • Granato piropo
  • Granato spessartite
  • Granato stellato
  • Granato tsavorite
  • Grandidierite
  • Howlite
  • Hyalite Opal
  • Idocrasio
  • Il geode di agata
  • Kunzite
  • Labradorite
  • Lapislazzulo
  • Larimar
  • Madreperla
  • Malachite
  • Matrice di occhio di tigre
  • Maw-Sit-Sit
  • Morganite
  • Nuummite
  • Occhio di gatto actinolite
  • Occhio di tigre
  • Occhio di tigre blu
  • Onice
  • Opale
  • Opale cioccolato
  • Opale doppietta
  • Opale macigno
  • Opale nera
  • Opale di fuoco
  • Opali in Matrice
  • Ossidiana
  • Ossidiana fiocco di neve
  • Peridoto
  • Perla
  • Pietersite
  • Pietra di Luna effetto occhio di gatto
  • Pietra di luna
  • Pietra di luna arcobaleno
  • Pietra di luna stellata
  • Pietre cangianti
  • Pietre stellate
  • Pirite arcobaleno
  • Prehnite
  • Pyrite
  • Quartz With Marcasite
  • Quarzo
  • Quarzo citrino stellato
  • Quarzo effetto occhio di gatto
  • Quarzo fragola
  • Quarzo rosa
  • Quarzo rosa stellato
  • Quarzo rutilato
  • Rodocrosite
  • Rubino
  • Rubino in fuchsite
  • Rubino stellato
  • Rubino zoisite
  • Scapolite
  • Scapolite effetto occhio di gatto
  • Scolecite
  • Serafinite
  • Serpentinite
  • Sfalerite
  • Sfene
  • Sillimanite
  • Sillimanite effetto occhio di gatto
  • Smeraldo
  • Smithsonite
  • Sodalite
  • Spectrolite
  • Spinello
  • Tanzanite
  • Topazio
  • Topazio imperiale
  • Topazio mistico
  • Tormalina
  • Tormalina rubellite
  • Turchese
  • Variscite
  • Zaffiro
  • Zaffiro cangiante
  • Zaffiro stellato
  • Zircone
Main Categories
  • Nuovi arrivi
  • Lotti di gemme
  • Gemme calibrate
  • Gemstones By Piece
  • Le pietre di massimo livello
  • Coppie
  • Gemme in cabochon
  • Drilled Gems, Briolettes and Beads
  • Le pietre portafortuna
  • Pietre incise
  • Gemme fantasia
  • Pietre stellate
  • Zaffiro non riscaldato
Solo per i clienti di lingua inglese

Gratuito - Solo USA e Canada:
1-800-464-1640

Internazionale:
+66-39303404

Risparmia denaro
Senza spese di spedizione per articoli aggiuntivi!
$8.90 spedizione in tutto il mondo

Update Translation
 
Current Value
New Value
GemSelect Gemstones
X Chiudi finestra
Colored Gemstones
X Chiudi finestra
Colored Gemstones
X Chiudi finestra
Colored Gemstones
Dimensioni e peso

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

Size Comparison Chart