Heated vs unheated sapphire: what buyers should know
· GemColony
Heat is the norm
Heating is an accepted, widely used treatment for sapphire and ruby. It can improve colour and clarity, and the great majority of sapphires on the market have been heated. The treatment must be disclosed to the buyer.
Why unheated stones cost more
Unheated stones with good colour are rarer, so they usually command a premium over comparable heated stones. The premium depends on size, colour and origin, and a buyer will usually ask for a gemological laboratory report to confirm it.
What a dealer should record
For every sapphire: the treatment status as reported, the laboratory and report number, the origin if stated by the lab, weight and dimensions. Keep the report with the stone record so it can be shared with a buyer and printed on the invoice.
Where AI fits
Image-based tools, including GemColony's AI analysis, can suggest likely type, clarity and treatment from photos. Treat that as a second opinion and a time-saver for sorting, not as a replacement for a laboratory report.