Gemstone Treatments
Most people don't realize that when they purchase a loose gemstone or finished piece of jewelry that the gemstone has probably been treated in one way or another to enhance it's looks. Most treatments involve heat, pressure or radiation. In some cases it is a combination of methods.
In the case of Ruby and Sapphire the color and clarity of the stone has often been improved by a High Temperature heat treatment process.
Heat Treating
Heat Treating is a very specialized high temperature process that will improve the color of most pale colored sapphires. We are one of only two retail stores in North America that own and operate our own heat treating furnaces. Most people prefer the darker color saturation and improved clarity of a heat treated gemstone.
The heat treating we undertake is considered natural within the industry because we do not add any artificial ingredients, chemicals or flux to artificially influence the color of the stone. The color developed within the gemstone through our heat treating process is totally dependant upon the naturally occurring ratio of iron to titanium within the stone.
One of our Heat Treating Furnaces
Pure sapphire (the mineral corundum, Al2O3) is colorless. Trace amounts of Iron, Titanium and Chromium are what give the sapphire color. Heat treating is an industry standard method for improving the color of sapphire.
We complete a two step process to heat treat sapphires. The first stage is the "Fancy Burn". Approximatly 15% to 20% of the stones will turn yellow or orange. The stones with good fancy colors are removed from the crucible and the remainder run through the "Blue Burn".
There is no way to predict or gurantee what color a sapphire will turn when heat treated; However, there are some general guidelines. In general the stone will follow the color trend of the natural rough. If the stone is yellow or orange to begin with, more than likely it will become a more vibrant yellow or orange. However, even a few of the pale green stones will become yellow or orange during the "fancy burn". Most of the sapphires, 80% to 85% look best after the "blue burn".
Fancy Burn
We start with the "Fancy Burn" in a pure oxygen environment. The photo above shows the bottom of a bulk crubilble used to heat treat a large quantity of rough stones for the store. All customer orders are handled individually in their own crucible. After the fancy burn we evaluate each stone individually and remove the stones we feel have good enough color saturation to be faceted.
Blue Burn
Most of the sapphires look best after the blue burn. The color will vary from spectacular blue to teal green. The natural ratio of iron to titanium within the stone determines the final color.
The heat treating we do is considered "natural" within the industry because we only use heat and do not add any artificial ingredients. Heat treating is an industry standard treatment for sapphire and totally permanent.
Beware of sapphire gemstones displaying "neon" color. Sapphire can be heat treated with the addition of chemicals to artificially color the stone. We do not use any flux or chemicals. The color achieved is purely dependent upon Mother Nature and the natural ratio of iron and titanium within the stone.
We specialize in heat treating sapphires from Gem Mountain. The price starts at $29. Heat Treating is billed either by the stone or by the carat, whichever is greater, at $6 per carat up to 20 carats. Quantity Discounts are available.
Please phone 406.859.GEMS (4367) for more details.
(We'll get the complete pricelist on the website some day).