Hi Steve.

Black Vitrified Ceramic aka BVC is a thouroghly baked ceramic with a high silica content. Vitrified actually means to be made glass. Thus the hardness is uniform from service to center. I have used ceramic before but not the BVC. The report from people trying it is parallel to my own experiences with other ceramics so I am guessing the black color is a marketing ploy. I use ceramic for tools a lot but no longer, I have found a superior composite tool. Vitrified is far superior to unglazed ceramic but it is still subject to lack of consistancy and rollout. This is where larger very hard grains come out un stress of grinding. Maybe it is Murphys law or you just don't notice it as much but rollout always seems to occur during the fine grinding stage with a 120 grit size scratch. I have heard that BVC tests worse for CoE than Plate glass and I can get Pyrex or equivalent for less.

I know and have heard of several unhappy BVC cutomers. I heard of one Happy customer with a small mirror but the claims are worse the larger you go.

You might check around the archives of the various boards or do a Google search on BVC.

If you try It I would like to hear about your results but for me I am going to stick with the pyrex cause it cost less and is a accepted as a superior product.

Good Luck, -Rick