Is Heat Treating Gems Bad

The heating process is in fact just a way of artificially enhancing the colour of a gemstone. It does no harm but to say a gemstone has been unheated when it has been is not being truthful. A stone that has no heat treatment can be tested and certified by a GemLab.

How do you tell if a gemstone has been heat treated?

Heat treatment is a very risky process as many gems have inclusions that expand at a different rate and cause stress fractures, which then becomes an identifying characteristic of heated gems, particularly sapphire and ruby which can display halos around inclusions within the gem.

Are heated gemstones less valuable?

Does heating a gemstone lower its value? For lower-priced gemstones, the price between heated or unheated won’t differ too much generally. For example, a carnelian that is heated for its fiery orange color won’t have a much higher price tag than an untreated one.