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Tuesday, November 07, 2006

How to judge Topaz

TOPAZ is a beautiful gem that radiates feminine grace with its unique colour transition. It is one of the most popular and common coloured gemstones in the market. Because it comes in a wide range of sky blues and radiant azure blues, many people associate it with the colour blue. The fact is, topaz also comes in many other colours.

There is a marked distinction in quality and value between the various colours of topaz. The golden, orange, pink, red colours – the finer grades – are termed ‘precious’, and are the ones that attract consumers and jewellers alike. These stones are often heat treated to improve their colour.

The term ‘imperial’ is confined to a certain range of colours and intensities, such as the red, deep pink and reddish orange colours. The imperial topaz colour is a magic blend of rich sherry (pink orange) with red flashes. Well-proportioned stones are highly desirable. Overall, topaz is reasonably clean.

Treatments
Several varieties of topaz are treated to improve their overall colour quality, and the most common treatment is a combination of irradiation and heat. Over 99 percent of all blue topaz sold today are the products of treatment. Depending on the type of treatment used, light to medium ‘aquamarine blue’ is produced, as well as deep ‘sky blues’, colours that are not normally found in nature.A fair percentage of brown topaz and possibly other colours may have resulted from natural irradiation. Some brown topaz fade on exposure to sunlight. All treatments should be disclosed at all levels of the distribution chain. If you are doubtful, consult a reputed gem testing laboratory.

Imitations
The most frequently encountered imitations of topaz include citrine, smoky quartz and man-made stones such as glass. With a wide variety of colours and high lustre, topaz is an affordable and attractive gem to own, especially if you like colourful jewellery and are not too particular about artificially treated gems.

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