Mary, if you hold your stein with the lid open and the base pointing toward a light source you will see an image in the base which is called a lithophane. It is made solely by the varying thickness of the porcelain in the base, no coloring agent of any kind. Most porcelain steins are not marked as to manufacturer, so the maker of your stein is destined to remain anonymous. It is old – circa 1900 – and has a value in the $50-$60 range.