got the GIA (http://en.wikipedia.org/wiki/Gemological_Institute_of_America) prior to purchasing the stone.
valuation came in about 5-6K more than payed for it.
the jeweler discounted massively if you get him to make one, as he knows it not going to sit in the window for 12 months wasting him money and maybe need a redesign or be in a sale.
first time ever custom cheaper than off the shelf
pretty happy all in all.