1. a class of soil minerals containing aluminum and silica in a 1:1 layer structure —note kaolin is composed of several minerals, the most common of which is kaolinite, and including halloysite and dickite 2. a soft, usually white, rock composed largely of kaolinite —note kaolinite is common in Georgia, where it is mined and sold to the paper industry for use as a coating on magazine-type paper to improve printability This definition last updated 10/28/2008