This is a set of three nesting mixing bowls made in the vaseline green glass Pillar Optic Ribbed pattern by Hazel Atlas. The bowls have a square base and I believe that they date to the depression era, 1930s. The set is missing the 7 3/4 top diameter bowl - I have the 6 3/4, 8 1/4 and 9 1/2 bowls. The set glows under an ultraviolet lamp (see photos). All three bowls are in excellent condition with no noted signs of use - there is a colour defect on the rim of the largest bowl, but this is inside the glass and original to its manufacture (see last close-up photo). These are not common, so are great additions to a either a depression kitchen glass or vaseline glass collection!