Dugan’s Wide Rib and Diamond’s Spiralex Vases

By Dr. Larry Keig

Not many Dugan or Diamond vases with twisted ribs, without other pattern elements, are Diamond’s Spiralex. The vast majority of Dugan and Diamond vases with twisted ribs are Dugan’s Wide Rib. Thus, the presence of twisted ribs on these vases is not pattern determinative. However, there are several ways to tell one from the other. Differences are summarized in the Table below.

The base colors confirmed in the two patterns are also revealing. Wide Rib vases have been verified in six colors: countless examples in peach opal, amethyst/ purple, oxblood/fiery amethyst, and white, apparently a few in marigold, and, at present, at least two in blue. Spiralex have been authenticated in marigold, blue (the commonest color), and sapphire with marigold overlay and may also be available in amethyst. Thus, the peach opal, amethyst/purple, oxblood/fiery amethyst, and white are almost certainly or very likely Wide Rib. The blue and sapphire are probably Spiralex. No peach opal Spiralex are known and are not likely to exist as that surface color was phased out of production in the early teens, a few years prior to the introduction of the Spiralex pattern.

The hope here, with the distinctions between Dugan’s Wide Rib and Diamond’s Spiralex noted, that the confusion between the two twisted rib patterns can be eliminated or substantially reduced. Wide Rib vases identified as Spiralex is an error that occurs far too often.

For a starter in pattern identification, use the thumb test on the outer edge of a flame. If it’s bulbous, the vase is Wide Rib, If it’s not, it’s Spiralex. After that, run your thumb down a rib. If it feels thick to the touch and is heavily raised, it’s Wide Rib. If it’s thin and only slightly elevated, it’s Spiralex. Finally, check the other characteristics in the table to affirm or disconfirmed your earlier conclusions.

At left is a purple Dugan Wide Rib vase. To the right is a sapphire Diamond Spiralex vase.

You can see the more bulbous tips on the top points and the wider more pronounced ribs of the Wide Rib on the left above. The tips and ribs aren’t as pronounced on the Spiralex on the right.

The Wide Rib has more pronounced ribs, left, whereas the Spiralex, right has thin, slightly raised ribs.

Photos courtesy of Matthew Wroda Auctions and the editor.

Dugan’s Wide Rib and Diamond’s Spiralex Vases

This article first appeared in the ICGA Pump in the March 2024 issue and is reprinted with permission.