As Reported in Modern JewelerApril 2003...

Chanthaburi Gem Traders & Heaters Association in Thailand admitted using beryllium to color gemstones.  The process  is described as "Thermal enhancement of corundum together with other minerals in an environment that allows beryllium and other elements into corundum.

It was found orange sapphires could be produced by placing sapphires in a crucible with beryllium rich crushed chrysoberyl and then heating the mixture.