What Is Heat Treatment? Heat Treatment is a gemstone’s exposure to high temperatures that alters the color and increases the clarity. Specifically, heating is used to lighten, darken or enrich the color. Without heat treated gemstones, fine gems’ availability in the most desirable colors would be scarce.
Are heated gemstones bad?
Durability: Since most gem crystals were formed under high temperatures, when it comes to wearability and durability heating usually does not have a negative effect on a gemstone. Also, the color stability (resistance to fading or color changing) of heated gems is usually very good and they are super stable.
What is the difference between heated and unheated gems?
The difference between Unheated and Heated Sapphire is like the difference between processed and natural food. Natural food is always healthier than processed food. The heat-treated Sapphire lost its effectiveness almost to zero.
Are most gemstones heat-treated?
Heat – gems exposed to high temperature to permanently alter their color. One of the most common gemstone treatments; for example, over 95% of all rubies on the market today are heat-treated. In most cases the treatment improves the gem’s apparent color and/or clarity.
Are heat-treated gems less 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.
Which gemstones are not treated?
Untreated Orange, Brown, and Rose Zircon Gemstones
While the popular blue zircon is heat treated, there are natural zircon gems that are not treated in any way. These include brown, rose, rose-orange and golden orange zircon gemstones.
How do you heat treat gemstones at home?
How to Heat Treat Gemstones
- Place the raw gemstones in a crucible after you thoroughly clean them. …
- Raise the temperature of the oven to approximately 1,600 degrees Centigrade. …
- Allow the gemstones to cool until you can sort them.
Are all gemstones heated?
Out of all gemstone treatments, heating is one of the most widely accepted. Some people view it as an extension of the gemstone’s formation, as the heat could have been applied by the earth before they are mined.
Are heat treated sapphires good?
Are heated sapphires undesirable? No, the important factors for a desirable gemstone are: a beautiful color, eye-clean clarity, well-cut, and pleasant crystal. However, heated sapphires do lack the natural and rarity appeal of unheated sapphires.
Are heat treated sapphires less valuable?
Most people are unaware that almost all sapphires are heated at extremely high temperatures to “enhance” their color and clarity. Natural untreated sapphires are far more uncommon and valuable than treated and chemically altered stones. …
How can you tell if a gemstone is heat treated?
Heat treatment is a very risky process as many gems have inclusions that expand at a different rate and cause stress fractures, which then becomes an identifying characteristic of heated gems, particularly sapphire and ruby which can display halos around inclusions within the gem.
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.
What does it mean when a gemstone is coated?
Many gemstones have been routinely coated to improve or radically change their color for many years now. Topaz is a case in point. … It has the effect of improving the color. The treatment involves applying a coating consisting of cobalt, to pale Tanzanites in order to give them the appearance of fine stones.
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.
What does it mean when a gemstone is unheated?
It is a stable and absolutely tolerated process on the gemstone market. … This is what is more commonly known as “unheated” stones. An unheated ruby or sapphire, with a certificate of authenticity, will see its price increase all the more quickly as the colour is beautiful and the stone important.
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.