A process for producing iron-containing biscuit-fired ceramic which comprises firing a cylindrical article containing as the active ingredients monazite and a Paleozoic to Mesozoic clay including a fossil bed mainly comprising diatomaceous earth at 700 to 1,100 DEG C in a reducing atmosphere. An eco-environmental water prepared by treating water with the ceramic has a high physiological activity on both animals and plants and its quite effective in retaining and enhancing the vital force.
