Diamond Ruby & Sapphire Emerald
Laser drilling is commonly used to enhance the clarity of diamonds. A focused laser beam is used to drill a narrow tunnel from the surface of the diamond to the dark inclusions inside the diamond which may then be acid bleached. Fracture filling treatment is done to improve the clarity of diamonds. Surface reaching breaks in a diamond are filled with a transparent substance. Artificial irradiation treatment is used to improve the colour of diamonds. The diamond is bombarded with radioactive particles which produces a green colour which can be further enhance to attain fancy yellow, orange or rare pink colour. Heat treatment is widely used to enhance the colour producing bright red hues in rubies and intense blue hues in sapphires. Cavity filling is a common treatment in which glass like substance is applied to seal surface pits and cavities, add weight and improve the overall appearance of rubies and sapphires. Oiling and infilling are very common treatments for emeralds. Surface reaching breaks in emeralds are filled with various types of oily organic substance such as cedar wood oil, palm oil or artificial substance such as opticon.
Aquamarine Citrine Opal
Heat treatment of green-blue aquamarine is commonly done to produce beautiful sky blue hues. Heat treatment of amethyst produces most citrines. Impregnation with colourless oil, wax or plastic is sometimes used to enhance the play of colour and hide the cracks of poor quality white opal.
Tanzanite Topaz Tourmaline
Heat treatment of tanzanite produces violet and deep blue colours. Most tanzanites are heat treated. Heat treatment and irradiation is able to produce pink, orange, brown and blue topaz. Irradiation is common and produces deep pink tourmalines.