Updated: Nov 4, 2020
When it comes to buying colored gemstones (i.e. rubies, sapphires, emeralds, etc.), what many don’t know is that more than 90% of the world’s supply has undergone treatment. This should not cause you any alarm. However, if your jeweler is trying to pass on their selection of colored gemstones as untreated, then their integrity or at least expertise may be in question.
Heat treatment of colored gemstones to enhance color is an accepted practice in the industry. What you should be avoiding is any treatment done on colorless diamonds as this may mean overpaying for the actual value you are getting.
Untreated colored gemstones are more uncommon and much more valuable. Make sure they are certified by AGS or GRS.