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Gem Treatments

Gemstone Enhancement Treatments

Many gemstones have undergone some form of enhancement treatment.  Gems are treated to improve appearance and/or durability.  Where treatments are considered standard practice, it is often not considered necessary to disclose them to the buyer.  However, we believe that every customer has the right to full disclosure about any enhancement treatment.

In recent years, new enhancement treatments have appeared which significantly alter the colour and appearance of gems.  In some cases, these treatments can also greatly influence the value of the gemstone.  Therefore, it is very important that buyers insist on full disclosure of any gemstone treatments before purchasing.  See below for more information on various enhancement treatments. 

Please note that Aussie Sapphire will always state treatment status of all gems from our mine in our Certificate of Origin and only basic heat treatment is used where necessary.  Information on treatments of imported gems will be given where available - we only buy from reputable suppliers but we cannot guarantee status of gems that we have not actually dug out of the ground ourselves.
The following is a short description of some of the treatment methods used on a variety of gemstones.  In the case of corundum treatments (heating and bulk diffusion), please follow the links for more detailed information on this issue.

Basic Heat Treatment:

Basic heat treatment of sapphire is standard for the industry and buyers should assume that all sapphire has undergone this process unless otherwise stated with supporting paperwork (lab certificate, etc). This simple process of heating the sapphire has been carried out for centuries and is a stable, permanent process which improves the appearance of many sapphires as it simply finishes the natural process.

Please see our Heat Treatment page for more information and links on this topic.
Bulk Diffusion:

Bulk diffusion or beryllium treatment is a new treatment that significantly alters sapphire colour through the use of chemical additives during an ultra-high temperature heating process.  Although detection is difficult, evidence of very high temperature heating (> 1800 °C) sometimes for extended periods is indicative of bulk diffusion treatment.

This treatment is extremely common in sapphire other than blue - you should assume that all yellows, oranges and padparascha colour sapphires have been treated in this way unless you have specific written documentation to say otherwise. Unfortunately, it is now clear that this type of treatment is also used to create a desirable colour of blue.  Therefore, all buyers should demand written guarantee of treatment status before purchasing. Do not pay more for fine colour if this colour is not natural - this value is artificial so beware.

Reputable sellers will disclose this treatment using terms such as bulk diffusion, lattice diffusion, beryllium or Be treatment.  Aussie Sapphire does not support the use of this type of treatment and do not treat any of our gems in this way.

Please see our Bulk Diffusion information page for a comprehensive list of links and further discussion on this important issue.


Gems such as blue topaz and fancy coloured diamonds (including black) are routinely irradiated to create these colours.  This is a permanent and routine treatment and therefore will not be disclosed to most buyers.  The use of radiation to create/alter gemstone colour is safe as long as gems are treated in the recommended manner and stored for the correct length of time ("cool-down" period).

Oiling or Resin Infusion:

This treatment involves the introduction of a colorless oil, wax, natural resin, or similar product into fissured or porous gemstones in order to improve appearance. Commercial grade emerald is routinely enhanced in this manner.  It is considered misleading practice to use a coloured substance - for example, the use of a green tinted substance when treating emerald is not recommended (but sometimes occurs).  This treatment is not considered permanent although will be long-lasting if the gem is treated with care (no ultrasonic or steam cleaning, harsh detergents, etc).  This treatment in emerald is routine and would not normally be disclosed to buyers. 

Fracture filling:

This treatment is used to fill or repair surface-breaking cavities or fissures with colourless glass, lastic, solidified borax or similar substances.  This process may improve durability, appearance and/or increase weight.  This treatment is often used on ruby (sometimes called "lead-filling").


Dyeing refers to the introduction of a colouring agent into a gemstone to give it new colour, intensify colour or improve colour intensity.  Black onyx is routinely dyed to create black colour.  Fancy coloured pearls are often dyed to create rose, gold or blue overtones.

Other Treatments:

Other treatments include Lasering (use of lasers to alter inclusions within a gemstone), Coating (surface enhancements to create special effects), Bleaching (treatments to lighten or remove colour), etc.  The other enhancement method which should be mentioned is Composite Gemstones (or assembled gemstones) which are constructed of multiple layers or combinations of materials.  An example of this would be an opal doublet or triplet.  As these composites often have different care requirements to their fully natural counterparts, these should be disclosed to buyers at all times.

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