Glass ingots from the world's oldest shipwersk, 3,300 yrs., off Turkey. ~24 round cakes (6" x 2 1/2", 5 lbs.) have been recovered so far. They are the earliest intact glass ingots that have ever been found. The glass is blue in color, cobalt being the coloring agent. Cobalt blue glass was extensively used in New Kingdom Egypt for glass vessels and in the Mycenaean Greek world for glass jewelry.