A limestone with argillaceous composition (clay mineral) of 25% -50%. Except for mud, the content of carbonate minerals ranges from 50% to 75%. It is often earthy yellow in color, with microcrystalline and fine-grained structures, and sometimes contains a small amount of yellowish brown siliceous nodules. Foaming when exposed to dilute hydrochloric acid.
Natural materials and products -> Mineral materials