Attached Link: http://www.3dlapidary.com/Home.htm

Hi aprilgem. Here's a terrific site for 3D gemstone models with really good suggestions for rendering the models to look like actual gems. P.S.-Last time I checked many of the models were in .dxf format, but there are a lot of freeware 3D file convertors to change them to the file formats you need. HTH