About gemstone valuation

In order to determine the correct value of any gemstone, correct identification is paramount. Assessment of gemstones not only includes whether they are natural, synthetic or artificially treated, but the quality of the colour and clarity of gemstones needs to be taken into account to determine their value. Laboratory testing equipment is required for the scientific analysis of precious and semi-precious gems for correct identification. Recognition of jewellery manufacturing techniques pertaining to imported and local jewellery is essential as well as an understanding of antique and period pieces.

Gemstones may be treated in some way to enhance the colour or transparency. These treatments are generally accepted in the jewellery industry worldwide, however they need to be identified as they can affect the value. These enhancements may include heat treatment, fracture filling and surface filling, beryllium diffused rubies and sapphires, irradiation, coating, dyeing and oiling etc. New treatments are constantly being developed as well as new technology and new scientific methods to detect them.

Precious metals need to be identified, as the stamp on the jewellery may not necessarily be correct. The precious metal purity is normally that marked on the article. When testing precious metal it may be considered necessary to utilise small amounts of acids to determine the precious metal purity.

Currently many diamonds are accompanied by diamond grading reports from independent laboratories. Ian is able to verify the accuracy of these reports.