LOTR TNC Vilya, The Ring of Elrond

Hi every one,

I was lucky to get a hold of a rare NC Vilya ring.
It is the 10K version but the odd thing is, the stone looks black.
Was this common when this where offered by The Noble Collection?

Does any one have a recommendation on how I can replace the stone with A Blue Sapphire?

See my listing here of the ring:
Vilya, The Ring of Elrond (10k Gold) The Noble Collection movie props from Lord of the Rings Trilogy

Thanks