Hemp was originally used to make canvas.
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.