Quote Originally Posted by TheMetatron View Post
The little scrap of paper information sheet that came with them said they're made from high alumina ceramic, formed when alumina particles (synthetic sapphires) are mixed with a ceramic bonding agent, then fired to make the final shape. I'd think it is the size of those alumina particles that are determining the grit of the fired ceramic.
If you check with the company, they will tell you that the two plates are made with the same alumina particles and the same ceramic, and that the only difference between the two plates is in the surface lapping.