Enhancement, explained and declared
Almost every coloured stone you have ever seen in a shop window has been enhanced in some way. Heating sapphire and ruby is among the oldest practices in the trade, dating back centuries, and it is accepted worldwide: it deepens colour and clears internal silk in material that would otherwise never be cut at all. Roughly 95% of sapphire sold anywhere in the world has been through it.
Enhancement is not a flaw. It is a normal, stable and permanent part of how coloured stones reach the market, and a well-enhanced stone is a sound purchase at a sound price. What matters is that the buyer knows exactly what they are getting, which is why every card here states the process, the certifying laboratory and the country of origin.
There is a real difference between simple heating and a lattice or diffusion process, and a further difference again from a filled stone. Those are distinct treatments with distinct values and distinct care requirements, and the listings separate them plainly rather than grouping them under one word.
