Calculus (medicine) - Wikipedia
https://en.wikipedia.org/wiki/Calculus_(medicine)A calculus (plural calculi), often called a stone, is a concretion of material, usually mineral salts, that forms in an organ or duct of the body. Formation of calculi is known as lithiasis (/ˌlɪˈθaɪəsɪs/). Stones can cause a number of medical conditions. Some common principles (below) apply to stones at any location, but for speci…