[PapaBear]

I was thinking about nothing in particular while my wife was making a mosaic tabletop out of broken ceramic tiles and it occured to me that the clays used in the tiles are essentially the same as those used in Koi Clay and ceramics ie bakki media. My thought was that they could possibly be used as an augment to a TT or other similar shower much as Oyster shell would. The only concern would be the mineral/metal additives used on the top surface for coloring the tile itself before it is glazed. Anyone have any experience on the colorants/glazes used when they are fired??? I know some pottery colorants are lead based but that is a slightly different process.