Yellow Sapphire goes clear!

Another shop has brought my boss a ring, gold band with a big yellow
sapphire. At least he says it WAS yellow, until he put in sizing
balls, now it is clear. This means that it was naturally coloured
yellow, not irradiated like most. If this ever happens to you, put
the stone under a black light (UV?) for about 4hrs, and the colour
should come back. Weird eh?!
karen from vancouver