Blue diamonds are mainly mined in South Africa in the De Beers deposit. Such finds are extremely rare, about once a year. Therefore, natural diamonds found in bright blue cost hundreds of thousands of dollars per carat.
In nature, lighter shades, slightly blue, are more common. It is them, thanks to modern technologies, that can be significantly improved and a brighter color can be obtained. In the natural environment, blue diamonds have been forming for thousands of years.
Experts have learned to imitate natural phenomena in laboratory conditions. This is called diamond refining.
The process does not make the stone artificially created and it is not a fake. It also remains natural, but with improved color. The chemical structure does not change at all.