How does treatment affect the value of a gemstone?
Generally this is determined by the type of treatment applied. Heat treatment is a very common practice and in most instances, difficult or impossible to detect. This is because the metamorphosis that occurs during heat treatment process closely resembles what would have occurred naturally during its formation. For this reason, heat treatment does not generally affect the value of a particular gemstone unless glass filling of cavities is also applied during the heating. Despite this, however, a certified untreated stone will always command a higher price due to its rarity, and the premium could be as much as 50%. The effect of other treatments on gemstone value varies from case to case and depends on the treatment techniques employed, its commonness, and the gemstone variety that it is applied to. Virtually all emerald is treated by colorless oil and in general the prices already take this into consideration. Emeralds that require no treatments are extremely rare and will be valued sev
