Blue white swirl graniteware enamel square pan

A wonderful turquoise blue graniteware enamel pan with black rim trim. Would be great for lasagne. Measures 2 1/2" deep, and is 11" x 13" rectangular shaped.No chipping to the inside or outside except for small edge chips just on the black rim. A beautiful pan and nice and heavy. No visible wear or utensil marks on inside or outside. Not sure of the age and no makers marks