A microkernel implements all drivers as user-space programs, and implements core features like IPC in the kernel itself. A monolithic kernel, however, implements the drivers as a part of the kernel...
Porcelain is made with kaolin clay. Kaolin is white clay that retains its white color when fired. It is fired at temperatures in excess of 1300 C and is more fully vitrified than stoneware. It is usually covered with a clear glaze, which allows the white body to show.
Porcelain is also a champ at shrugging off water. It may sound simple, but a porous material will allow liquid and bacteria in, so being impervious to both is important in a structure that's main job is to deal with waste. The key to keeping water out is in the porcelain's glaze. After the toilet is coated, it's fired in a kiln. Unlike, say, grout in a shower, which takes on both water and bacteria, the glaze stops bacteria at the toilet's surface.