Diamond Optic, Fenton
Probably more stretch glass than Carnival, Diamond Optic was produced in a variety of shapes and colors in the late 1920s. This water set is the first I've heard of in this shape. In celeste blue, it sold in 2012 for $170.

In 2019, a perfume bottle in pink, with the bottom of the stopper missing, sold for $200.

In 2022, this rosebowl, 4 inches wide with a 2 1/2 inch base sold for $40. The color was listed as Tangerine. Photo courtesy of Seeck auctions.

Updated 5/25/2022