Great tutorial. I've been taking pictues of jewley for a while and I have always had trouble getting the set-up quite right. 

I just thought I would add that scanning jewlery has given me some really  great images.  I usually lay the item out on the scanner bed and then use a white shoe box top to  cover the piece so that the scanner lid doesn't alter my set-up. 

Then  hit scan and... voila!