The first colored opal PYREX items were the 4-piece Primary Colors mixing bowls which were offered in November 1945. This set marked the first time PYREX sold opal "milk" glass with applied colors. The mixing bowl set included blue, red, green and yellow while the refrigerator set, launched in late 1947, included red, blue and yellow. The earliest Primary Colors mixing bowl sets, from 1945-1949 did not have model numbers (401, 402, 403, 404) or capacities listed on the mixing bowls. In…