The great majority of sapphire and ruby sold worldwide has been heated, some of it to very high temperatures, to improve or create its colour and clarity. Heat is a permanent, widely accepted treatment. It is also a treatment, and it changes what a stone is worth.
An unheated stone of good colour is scarcer, and so more valuable, than a heated one that looks the same, because the unheated stone earned its colour in the ground rather than in a furnace. Both are real. They are not worth the same.
Our rule is disclosure, every time. If a stone is heated, we say heated. If it is unheated, we say unheated, and we would rather you sent it to an accredited laboratory before it ships than take our word for it. A treatment named is a stone you can price. A treatment hidden is the thing we exist to be the opposite of.