|Five Zero One (501), Dugan|
|This photo of an extremely rare Dugan #501 vase was sent to me by King Hoppel in 2013. It is just over 6 inches tall with a 2 3/8-inch square base and is square ruffled. The vase has a Royal Lustre treatment over cobalt blue base glass.
A vase described as this pattern in blue sold in 2015 for $30.