Rainbow - Northwood
Few collectors pay much attention to these as there is really no pattern except for the basketweave on the exterior. There are even bowls and plates with no pattern on either the interior or the exterior. They are usually marked with the Northwood mark though. The name comes from the color spectrum displayed on the interior with the iridescent color bands radiating out from the center.

Found in pie crust edge or ruffled bowls, 9 inch plates and compotes in green, marigold and purple.