Vintage coffee mug advertising for The American Fire Clay & Products Company in Canfield Ohio. About 3 1/2 inches tall with great graphics. Bright white milk glass type material. Has a full 10 digit phone number so would date to about 1960's I believe. Cannot find any history on this company, just a couple other vintage items and a stock certificate (New Jersey) from 1910 listed elsewhere. There is no logo embossed on the bottom to identify who made the mug. It seems the fire clay may have been used to process iron into steel in the nearby Pittsburgh steel mills. The clay would have held up during the high temperature process, used as a lining in the ovens etc. The clay was mined locally also.