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

Diffusion Treatment

Diffused Blue Star Sapphire Cabochon
Diffused Blue Star Sapphire Cabochon

A treatment that one should be aware and cautious of is diffusion treatment. There is some controversy surrounding this method of treatment. Diffusion treatment consists of exposing the surface of a stone to certain chemicals combined with high heat in a furnace. Generally, only the surface color changes, so if you sliced the gem in half, the inside of the stone would be a different color, usually a paler, less valuable color. The problem is that the new surface color is not very deep, only about half a millimeter. If the stone is damaged or perhaps recut, then the original, undesirable color will be noticeable. Beware of this treatment. Nowadays, this method is used to change the color of ruby, green topaz, and blue sapphire. Usually the original material is a pale or almost colorless stone that is treated to change the color of the surface. Until methods are perfected whereby the entire stone color can be changed, reputable dealers will always tell you which stones have been altered by this method of treatment. Some dealers even refuse to trade in these stones.

However, for star sapphires, this practice is more readily accepted. GemSelect deals in star sapphires that are diffusion treated. Diffusion treatment is a popular method for treating star sapphire, since the treatment will increase the asterism (the star effect in sapphire and ruby). The diffusion process may reach a depth of half a millimeter into the gemstone. The process enhances the star effect on the gemstone and the stone can be sold as a diffused star sapphire. The hardness of the gemstone is not affected by the diffusion process, therefore the gemstone retains its original physical properties. A sapphire made into a diffused star sapphire cannot be polished for a second time or recut, as the treatment is only on the surface of the stone. Polishing or recutting would remove this surface treatment. However, most buyers never repolish or recut the gemstones set in jewelry. This is especially true of sapphires because they are hard and scratch resistant gemstones.

  • Prima Pubblicazione: September-04-2006
  • Ultima modifica: November-08-2018
  • © 2005-2019 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.).
Pinterest Board Names
More Shapes
Le pietre più conosciute
  • Zaffiro
  • Smeraldo
  • Rubino
  • Acquamarina
  • Zircone
  • Opale
  • Topazio
  • Tormalina
  • Granato
  • Ametista
  • Citrino
  • Tanzanite
Tutte le pietre preziose (145)
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
  • Calcite
  • Cat's Eye Augite
  • Cat's Eye Opal
  • Charoite
  • Cianite
  • Citrino
  • Clinohumite
  • Corallo
  • Corallo fossile
  • Cornerupina
  • Corniola
  • Crisoberillo
  • Crisocolla
  • Crisoprasio
  • Cromo diopside
  • Diamante
  • Diaspro
  • Diaspro cangiante
  • Diopside stellato
  • Druse emimorfite
  • 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
  • Geode di ametista
  • Geode di citrina
  • 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
  • Hiddenite
  • Howlite
  • 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
  • Opale
  • Opale cioccolato
  • Opale doppietta
  • Opale macigno
  • Opale muschiato
  • 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 stellate
  • Pirite arcobaleno
  • Prehnite
  • Pyrite
  • Quartz With Marcasite
  • Quarzo
  • Quarzo citrino stellato
  • Quarzo effetto occhio di gatto
  • Quarzo fragola
  • Quarzo fumé
  • Quarzo mistico
  • Quarzo rosa
  • Quarzo rosa stellato
  • Quarzo rutilato
  • Rodocrosite
  • Rodonite
  • Rubino
  • Rubino in fuchsite
  • Rubino stellato
  • Rubino zoisite
  • Scapolite effetto occhio di gatto
  • Scolecite
  • Serafinite
  • Serpentinite
  • Sfalerite
  • Sfene
  • Sillimanite
  • Sillimanite effetto occhio di gatto
  • Smeraldo
  • Smithsonite
  • Sodalite
  • Spectrolite
  • Spinello
  • Sugilite
  • Tanzanite
  • Topazio
  • Topazio imperiale
  • Topazio mistico
  • Tormalina
  • Tormalina cromo
  • 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