Heat treatment is used to improve a sapphire’s color, remove color zoning , and improve clarity. … Over the last couple of decades, high temperatures in excess of 1700 degrees Celsius has been applied to sapphires, which improves clarity by dissolving silk as it improves color.
Are heated sapphires still valuable?
Heating is an accepted treatment for sapphire. But for fine-quality sapphire, confirmation from an independent laboratory like GIA that there is no evidence of heat adds to a sapphire’s rarity and value.
Are heated sapphires bad?
Heat treatment alone does not affect the durability of sapphires. It is important to be aware that fracture filled or doublet sapphires can be problematic in future as they are less durable.
Does it matter if a sapphire is heated?
Most people are unaware that almost all sapphires are heated at extremely high temperatures to “enhance” their color and clarity. A sapphire can be listed as “natural” simply because it is not lab created. … However, “natural” does not mean the sapphire has not undergone any alterations.
What does it mean by heated sapphire?
Natural Heated Sapphires
These are natural blue sapphires that are heated in industry-accepted temperatures to enhance the intensity of the blue color and their clarity. This is a standard, legal, and stable process that does not impact the longevity or durability of the sapphire.
How can you tell if a sapphire is heat treated?
The study of inclusions in sapphires is a sure way to detect if a sapphire has been treated. Heating sapphires at extreme temperatures change the internal characteristics so much that it is quite easy for a trained gemologist to determine if the sapphire has been heated.
What percentage of sapphires are heat treated?
If a gemstone has been heat treated, it simply means it has undergone some type of thermal process in order to alter or improve its appearance. In this modern era, nearly 95 percent of sapphire gemstones are heat-treated for several important reasons.
Why are heated sapphires bad?
When Heating Affects Value Negatively.
In some instances, a sapphire could gain a “new” inclusion after heating; it could also heat to an undesirable or less valuable color. Choosing the right sapphires and the appropriate heating process takes many years, often times decades, of experience to become great at it.
How do you know if a sapphire is good quality?
You want to look for a sapphire that has no inclusions visible to the naked eye. experts look at the size, location and number of inclusions to judge clarity. The less visible the inclusions are, the higher the grade. Cut: The cut is essentially what makes a sapphire really sparkle.
Can you heat treat sapphires at home?
The easiest way to improve clarity and color of low-grade sapphires is to mimic the natural process and apply heat via an oven or furnace. Heating a sapphire at high temperatures specifically dissolves inclusions known as “silk” and other impurities, making the gemstone more valuable.
What is the difference between heated and unheated sapphires?
The color of a heat-treated sapphire will remain permanent and will not change or fade unless the stone undergoes a secondary treatment. … Some jewelry houses still prefer to offer only natural, unheated sapphires, but they would happily use a heated sapphire if it was requested by their client.
What are blue sapphires worth?
Sapphires can come as cheap as $25 per carat, to over $11,000 per carat. A blue sapphire around 1 carat is likely to cost from as little as $450 to $1,600, depending on quality.
Do sapphires fade?
The only colors of sapphires that are known to have a fading color property are yellow and padparadscha sapphires. … They exhibit this unique color fading and reviving characteristic as a feature of the stone’s natural design.
How are sapphires heat treated?
The heat treatment process is done to not only improve the clarity but also to “develop” the color of the stone. … The process of heating the rutile causes the titanium of the rutile crystal to diffuse into the sapphire crystal lattice, and in the presence of trace amounts of iron a beautiful blue color will develop.
Why are some sapphires cheap?
The price of a sapphire is determined based on its quality, which means that a large, low-quality sapphire would be a lot cheaper than a small but very high-quality sapphire. Blue sapphires usually have some inclusions, but generally have better clarity than rubies.
Are diffused sapphires worth anything?
These stones are not worth anything. This is because in their natural state the rough would have been an ugly, highly included gray color. That would NOT have been saleable if it was not subject to this type of treatment.