Blue Topaz Trillion Cut Gemstone
A number of techniques are used to improve color and appearance of natural and synthetic gemstones. The aim is to enhance their beauty, it is desirable, and saleability. Probably the oldest methods is that the heat treatment of gemstones to enhance or change color. Carnelian warming was made in India for over 4000 years and oiling of emerald was known for over 2000 years.
Following progress on technology, there are now many different techniques, using modern equipment such as lasers, and computer controlled heating and irradiating procedures. Lasers are used in diamond drilling to reach the inclusions. They are then evaporated or removed by chemicals before the crack is filled. Some treatments are permanent, such as drilling that others may be temporary. For example, stains and fillings can leak, some stones heated, irradiated, and can disappear or return to their original color.
Most rubies and sapphires are heat treated to improve their color. Sapphires found too dark color may have diminished by heating at 800-1400 degrees Celsius, in oxidizing conditions. Very pale gray-brown material from Sri Lanka called geuda can be changed to blue by heating at temperatures of 1500-1900 degrees Celsious in reducing conditions (without oxygen present). Variations in temperature and the conditions to allow more subtle color changes, some of which only reaches just below the surface while others change the whole rocks. Over Brown Topaz 100 years been heated to provide an attractive pink and amethyst citrine was changed to uncommon.
As well as heating, of precious stones may be irradiated to improve or change their color. They may be exposed to gamma rays or bombarded particles such as electrons, neutrons, protons, or alpha particles. Many colorless Topaz is irradiated and heat treated to blue.
Most emeralds have flaws or cracks that hijack attention from their beauty. Traditional oiling emeralds are a simple process. In essence, it is only a stone involves immersing in oil or deletion surface lines with an oily rag. The oil is then sucked into the cracks, with the result that they are less visible and the stone appears to be clearer and more color.
Nowadays varied colorless oil, wax, and plastics are used in a number of different gemstones. Some remain liquid, others, such as hard resin set in stone or as a surface layer. Turquoise, Lapis lazuli, jade and some chalcedonies are meeting in liquid paraffin or has a surface layer of wax after polishing, which has penetrated the stone to fill cracks and gives a better surface color. In addition, colored oils and resins are also used. Match the color of oils or resins the stone improves color and hide flaws.
If a stone was anointed may feel greasy or leave stain when removed with absorbent material such as a tissue. Years of wear or cleaning with ultrasound may displace any oil and filling the resulting cracks in the stone that will become more obvious and worst of rock will fracture.
Colorful paints and stains can be used also on some rocks. Agate is dyed to imitate stone or give more light, but rather unnatural looking greens and blues to pinks decorated carved parts. Quartz rocks were painted green to mimic Reference to imitate Jade and Ruby.
Stone crushing involves placing a piece of material to reflect, such as a sheet metal behind the stone to change or improve the color and stone to light. Thwarting was used in the UK especially during the Victorian era to strengthen costume jewelry made of paste (glass). Thin layers of gold, spike and other metals can be deposited on the surface of gemstones and crystals to give the area a flower. If the back of the stone is covered, as quality growth would mirror reflectivity and stone appear brighter, and taking the color coating. Quartz crystal coated with a surface layer of gold to give a pale
Learn more about gemstones treated and enhanced or about other gems at our mineral blog.
20x20mm Cushion-Cut 23ct Swiss Blue Topaz
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