An area of the Southern deserts on the Anadorlintor continent that is a flat plain of glass 40 miles across.
Legend states the glass sheet is the result of the epic battle between Tesral and Shu, the Pharaonic god of fire over the destruction of the Phoenixes when they would not bow to his will. The battle lasting three days and nights melted the desert sands forming the glass sea. Only Tesral departed the battle. The worship of Shu went into decline and ended. Tesral has been questioned about the Sea of Glass and agrees that this indeed how it was formed.
Some 7000 years later the glass is no longer totally intact. There are breaks and holes. Even whole cities have sprung up in the area. In the passing millennia the sand has had its way and the surface is no longer highly reflective.
The edges are ragged in some places having been pushed back a mile or more from mining the available cutlet. Glass near the edges is deemed unfit for magic. The glass at the center is the most prized and the hardest to get. Numerous crystal balls are said to be made from the glass. There certainly is a lot of it to be had. Like wise various magical mirrors benefit from the use of the divinely produced glass.
Reaching the Sea of Glass is a difficult journey far from wells or other water sources. There is no water to be had any place on the Sea or Glass itself.
The Lair of the Great Lessor Phoenix is said to be located in the sea of glass.