[thedoc (OP)]

Sandra Kay  asked the Naked Scientists:
   
My question is about diamonds.

A manufactured diamond will fluoresce purple under a black light. I was surprised that my cluster ring and wedding band were purple but my single 3/4 carat diamond was bright white. Is there such a thing as real diamonds (ie not manufactured) fluorescing under black light? Or could the only reason they fluorecse be because they are manufactured? How would the value of real v manufactured compare for like diamonds.

Thanks
Sandy

What do you think?

[Bored chemist]

From wiki
"About a third of all diamonds will glow under ultraviolet light, usually a blue color which may be noticeable under a black light or strong sunlight. According to the GIA, who reviewed a random sample of 26,010 natural diamonds, 65% of the diamonds in the sample had no fluorescence. "

So, yes, roughly a third of natural diamonds fluoresce.