Object of the Day: Blue Slag Glass

The term “slag glass” actually refers to two vastly different collectible items. In the first meaning, slag glass is an opaque, marbleized glass. Often called “marble glass,” or “brown malachite,” this slag glass takes various shapes and was a popular glass-making method for vessels in America in the Nineteenth Century.


The second meaning of “slag glass” refers to large chunks of glass which have an organic, natural shape similar to mineral deposits and rock formations. This type of glass, seen here, are remnants of glass left over in the kilns of large glass companies. There are as many different colors of slag glass as there are glass.

This bright blue chunk of slag glass was given to me many years ago and I’ve always enjoyed it. The fluid shape and brilliant blue color are extremely appealing. It’s difficult to believe that this was simply an accidental occurrence and not the design of a sculptor.