Which material is used to make fine porcelain?

• A. Limestone
• B. Sandstone
• C. Kaolin clay
• D. Gypsum

Answer: (C)

Porcelain relies on a very pure, fine white clay to achieve its smooth, dense, and translucent body. Kaolin clay provides the right plasticity when wet and, crucially, the chemistry and fine particle size that, when fired at high temperatures, form a tight, glassy matrix. This combination gives the characteristic whiteness, strength, and translucence of fine porcelain.

Limestone would bring in calcium carbonate, which can dull whiteness and alter melting behavior; sandstone is coarse and would produce a rough, porous texture rather than a smooth porcelain surface; gypsum is used for plaster and molds and does not develop the dense, vitrified body porcelain requires.