Fine rock dust can be used as a clay substitute for stoneware pipes. These pipes are used in plumbing, irrigation, and for drinking water. They are non-toxic, do not wear down or corrode, and are long lasting.
Rock dust is used as an to improve the properties of some clay rich minerals. This can then be made into pipes and fired. Clay and stoneware pipes, are non-toxic, do not corrode, and have a wide range of uses. Sewer pipe manufacture requires calcareous fine aggregates, that resist acid attack. Most quarries deal with granite or basaltic rocks, so calcareous fines may not be easily available.
Quartz rich granite dust can also be used as a glaze, but very little material is required for glazing, so this can only be a minor use.