Beautiful vintage Blenko Glass #537 freeform bowl in rich amber glass. This iconic design was introduced to the Blenko catalog in 1953 and is a classic example of early Mid-Century Modern American art glass. This example measures approximately. 4 inches tall at its highest point. The bowl is in excellent vintage condition. The glass is clean with no chips, cracks, or repairs. It displays beautifully and has a striking organic freeform shape. A unique feature of this piece is its strong UV reactivity. Under ultraviolet (black) light, the amber glass exhibits a vivid glow, making it an exceptional display piece for collectors of Blenko, UV-reactive, and manganese-containing glass. Perfect for collectors of. UV Reactive / Black Light Glass. American Studio Art Glass. Please review all photographs carefully, as they are part of the description.