Most canvas is made of cotton. More expansive canvas fabrics are made from synthetic fibres. For umbrellas, I suppose you are referring to the coating of paint outside. Presumably, the silver paint would help to reflect some of the heat and electromagnetic radiation from the Sun. The word ceramics comes from the Greek word keramos, meaning potter's clay.
Manufacturers make ceramics from such minerals as bauxite, clay, feldspar, silica, and talc.
Most ceramic products can withstand acids, gases, salts, water, and high temperatures. Not all ceramic products have the same characteristics. Porcelain is often called chinaware. All porcelain is pottery, in the sense that it is one of the highest members of the great pottery family. But not all pottery is porcelain by any means.