Infinite Sets. If you continue to study this subject you will find discussions about infinite sets, and the idea of different sizes of infinity. That subject has special names like Aleph-null (how many Natural Numbers), Aleph-one and so on, which are used to measure the sizes of sets.
For decades, glossy paper, the type used in magazines, was made using a white clay called kaolin (named after the Chinese region Kao-Ling where it was mined to produce porcelain).
Kraft bag paper: A paper made of sulfate pulp and used in the manufacture of paper bags. It normally has a greater bulk and a rougher surface than the usual kraft wrapping paper. Kraft wrapping paper: A paper made essentially from wood pulp produced by a modified sulfate pulping process.