The process of improving the colour of certain gemstones by painting the facets of the pavilion. It is also usedto improve the brilliance of some yellowish diamonds by painting the facets of the pavilion with violet dye which neutralizes the yellow and gives a water-white appearance. Stones so tinted areusually given a closed setting so as to conceal the tint.The process has been used for centuries, especially in the 16th century before the introduction of the brilliant cut. Tinting is also used on some specimens of Hyalite (water opal) from Mexico.
Tinting

Tinting
The process of improving the colour of certain gemstones by painting the facets of the pavilion. It is also usedto improve the brilliance of some yellowish diamonds by painting the facets of the pavilion with violet dye which neutralizes the yellow and gives a water-white appearance. Stones so tinted areusually given a closed setting so as to conceal the tint.The process has been used for centuries, especially in the 16th century before the introduction of the brilliant cut. Tinting is also used on some specimens of Hyalite (water opal) from Mexico.
References
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson



