This stone bathtub is called : Black Forest. Its material is famious marble: Black Forest Marble. It is black marble with white veins.
We use top grade Black Forest marble to carve this stone bathtub. You could see the white veins is clear and white enough,the black foundation is gloss after polished. To carve a stone bathtub, it is important to choose the best marble block. Othervise the surface will not has gloss at all!