Customers

What does Gemstone Treatment mean?

Treatment on gemstones refers to any human process (other than cutting and polishing) which improves the appearance (colour and clarity) or durability of a gem. Gems are treated in different ways like heating, surface diffusion, glass filling, beryllium diffusion, irradiation, fracture filling etc to alter their appearance.

According to a survey done by GIA in 2005 95% ruby and sapphires (blue and yellow) available in the market were treated by heat. In our experience more than 99% rubies and sapphires (blue and yellow) available today are treated in some way or the other.

What do I need to know before going shopping?

Always stay with a professional, independent jeweller with serious gemmological training. There can be a huge price difference in two gemstones that appear the same in colour and clarity due to heat treatment alone. And it takes good experience and good gemmological knowledge to be able to identify one from the other. So stay with someone with a good reputation for quality and expertise.

To be assured about your purchase always take certificate from a laboratory which work on international trade standards.

Coloured gemstone shopping is “business for the eyes and soul” as my Great grandfather once told me. You can’t buy a quality gemstone from someone claiming discounts and you can’t buy a quality gemstone based on a picture on your computer screen. Fine quality gemstones are never discounted because they are too rare. And buying a gemstone without seeing what it looks like to your own eyes is the last thing you would like to do during a wise purchase.

Guide to Types of Treatment in Gemstones

Heating

The stones which do not get sufficient colour or clarity naturally and are taken out from the earth to meet immense demand, they are heated in furnaces to a very high temperature, which causes the inclusions to deform and alter the colour, making it dark, light, more intense or of a different colour.

What does heat treatment do to the stone?

Heat rearranges the atoms in the stone. As in the case of ruby the stone is heated almost to a point of melting, which lets the aluminium oxide in the stone to reform to what is basically a new crystal structure. This lets the chromium reform to give off a better colour of red. The same can apply to a type of sapphire known as goudasapphires. These are milky white sapphires that turn blue and account for many of the promotional quality sapphires out on the market today.

Price difference in a heated wiz unheated gemstone:   For instance a 3.00 carat fine ruby from Burma of natural unheated colour can sell for as much as Rs 10,00,000 while a heated stone of the same colour can go for around Rs 1,00,000 and similar looking diffused ruby can be for Rs 5,000

Thus you will always want to have a proper gemmological evaluation done for any ruby, sapphire (blue or yellow) etc that you may want to own.

Diffusion:

Diffusion was originally used on sapphires. Chemicals, like beryllium were infused at high temperatures which actually penetrated the gems. Early diffusion only produced colour on the surface of the gem and was referred to as “Surface Diffusion”. Surface diffusion was easily detectable with immersion, and often with simple magnification.

Great advancements have been made in diffusion treatment in the last decade and it was discovered that if corundum is heated to very high temperatures for a long duration, the diffusion would penetrate the entire stone! It can improve colour and also give a totally different colour to the stone.

Glass/lead Filling:

Filling is used on gems with surface fractures or cavities. Glass, lead or other materials are used to fill these cracks and holes. This is commonly done to rubies. This hides the cavities and also improves colour of the stone.

Lead being a toxic substance is hazardous to health so lead filled rubies should not be worn on everyday basis.

Fracture Filling:

Filling is used on gems with surface fractures or cavities. Glass, lead or other materials are used to fill these cracks and holes. This is commonly done to rubies. This hides the cavities and also improves colour of the stone.

Lead being a toxic substance is hazardous to health so lead filled rubies should not be worn on everyday basis.

Before and After Fracture Filling

Irradiation:

Before
Treatment of Natural pale blue and white colour sapphire.
After
Irradiation treatment saphires turn bright yellow.

Irradiation means pounding material with subatomic particles or radiation. Irradiation is used to produce yellow sapphires from pale bluish sapphires. The colour produced through this process is not permanent and goes back to the original colour over a period of time.
Cultured pearls can be irradiated to produce gray or blue colors; but dyeing in these colors is more common.

Heating

Heating

The stones which do not get sufficient colour or clarity naturally and are taken out from the earth to meet immense demand, they are heated in furnaces to a very high temperature, which causes the inclusions to deform and alter the colour, making it dark, light, more intense or of a different colour.

What does heat treatment do to the stone?

Heat rearranges the atoms in the stone. As in the case of ruby the stone is heated almost to a point of melting, which lets the aluminium oxide in the stone to reform to what is basically a new crystal structure. This lets the chromium reform to give off a better colour of red. The same can apply to a type of sapphire known as goudasapphires. These are milky white sapphires that turn blue and account for many of the promotional quality sapphires out on the market today.

Price difference in a heated wiz unheated gemstone:   For instance a 3.00 carat fine ruby from Burma of natural unheated colour can sell for as much as Rs 10,00,000 while a heated stone of the same colour can go for around Rs 1,00,000 and similar looking diffused ruby can be for Rs 5,000

Thus you will always want to have a proper gemmological evaluation done for any ruby, sapphire (blue or yellow) etc that you may want to own.

Diffusion

Diffusion:

Diffusion was originally used on sapphires. Chemicals, like beryllium were infused at high temperatures which actually penetrated the gems. Early diffusion only produced colour on the surface of the gem and was referred to as “Surface Diffusion”. Surface diffusion was easily detectable with immersion, and often with simple magnification.

Great advancements have been made in diffusion treatment in the last decade and it was discovered that if corundum is heated to very high temperatures for a long duration, the diffusion would penetrate the entire stone! It can improve colour and also give a totally different colour to the stone.

Glass/lead Filling

Glass/lead Filling:

Filling is used on gems with surface fractures or cavities. Glass, lead or other materials are used to fill these cracks and holes. This is commonly done to rubies. This hides the cavities and also improves colour of the stone.

Lead being a toxic substance is hazardous to health so lead filled rubies should not be worn on everyday basis.

Fracture Filling

Fracture Filling:

Filling is used on gems with surface fractures or cavities. Glass, lead or other materials are used to fill these cracks and holes. This is commonly done to rubies. This hides the cavities and also improves colour of the stone.

Lead being a toxic substance is hazardous to health so lead filled rubies should not be worn on everyday basis.

Before and After Fracture Filling
Irradiation

Irradiation:

Before
Treatment of Natural pale blue and white colour sapphire.
After
Irradiation treatment saphires turn bright yellow.

Irradiation means pounding material with subatomic particles or radiation. Irradiation is used to produce yellow sapphires from pale bluish sapphires. The colour produced through this process is not permanent and goes back to the original colour over a period of time.
Cultured pearls can be irradiated to produce gray or blue colors; but dyeing in these colors is more common.