What kinds of inkstones are there and are they worth collecting?

Say the material of inkstone. The materials of ancient inkstones in China are quite rich, including iron, gold, silver, pottery, tile, mud, jade and lacquer. In the Ming and Qing Dynasties, the variety of inkstones was increased in the inkstone making process, and some materials that were not suitable for grinding, such as jade, ivory and feed, were also selected as inkstones, but that was purely for the needs of arts and crafts.