The beauty of natural gemstones is unrivalled, enhanced only by common means of treatment. Most gemstones on the market today have been modified in one way or another.A lot of treatments are carried out whilst the gem is in the raw crystal stage and it is often impossible to be certain what enhancements have been made to a particular gem. Our chart below highlights the most common treatments that certain gemstones undergo. It is occasionally the case that even in one design, treatments may vary. For example, in a collection of fifty tanzanite rings, whilst the majority will have been heat treated, several pieces may not have been. Enhancements often have an impact on the value of precious stones, with the highest prices paid for natural gems of fine quality that have not been enhanced in any way beyond ordinary cutting and polishing.