Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids. For example, granite, a common rock, is a combination of the minerals quartz, feldspar, and biotite. The Earth's outer solid layer, the lithosphere, is made of rock.
In the geologic sense of the word, rocks or stones are made up predominantly of inorganic minerals. There certainly are rocks like some limestones that contain a large proportion of biogeochemically produced minerals like shells or later alteration of the original biological material. Some rocks may contain some organic matter but it often doesn't survive the process of compacting and lithifying (turning into rock).
However, from the Wiki page, it sounds like gall stones are dominantly organic matter like cholesterol that may contain some inorganic material like calcium phosphate or calcium carbonate. So I wouldn't really consider them stone in the sense used in earth science but maybe there could be some gall stones that get trapped in sediments after a person dies and then turn into a tiny proportion of a sedimentary rock.