Vitreous China Basins
Vitreous china goes a step further and is made by coating porcelain or ceramic with an enamel made from powdered glass, giving it a glossy look. This special coating makes it only marginally more durable than ceramic and porcelain.
Vitreous china is an enamel coating that is applied to ceramics, particularly porcelain, after they've been fired, though the name can also refer to the finished piece as a whole. The coating makes the porcelain tougher, denser, and shinier, and it is a common choice for things like toilets and sink basins.