The difficulty in identifying glassware is that it often has no definite logo or backstamp, making it harder to name the manufacturer. Perhaps this is of no consequence, as Corning was never the manufacturer of Corelle-matching glasses. Even official glassware has always been manufactured by a third-party company, and made from ordinary glass. Although the Corelle brand name might be on the box, the glasses are not made of break-resistant glass.
In determining which glassware is official, the best option is to study the pattern and compare it to a real piece of Corelle. If every aspect of the design looks absolutely right, it might be a licensed product. In any case, if the butterflies look a bit odd, or not all the blossoms are represented, or there aren't enough dots between the snowflakes, it is probably a look-alike.
Libbey is the most noteworthy producer of glassware that matches early Corelle patterns. It is not clear whether every single one of their products of the 1970s was made with permission. There are examples of Libbey glasses that are licensed Corelle Coordinates, but there are many older ones with look-alike patterns in diverse styles and designs.
Libbey imitated Snowflake Blue, Butterfly Gold (some in amber glass), Spring Blossom Green (some in green glass) and Old Town Blue. It seems that this company made official glassware in each of these patterns too, plus Morning Blue. Woodland Brown glassware also exists that might be a Libbey product, and in that case, the design is printed on a white band near the top of the glass.
(Photo: Small Libbey glasses with a version of Wildflower.)
Additionally, there are Libbey glasses in Meadow, Indian Summer, Wildflower, Strawberry Sunday, Country Festival and Spice O' Life, but they seem to be look-alikes.
Libbey Glasses: This Butterfly Gold version has a coloured band on its rim. The Spice O' Life examples are inscribed with "Bonne Sante".
Closed-handle pitchers, beverage jugs and cork-top storage jars were marketed by Libbey with look-alike designs. They include Butterfly Gold, Spring Blossom Green, Country Festival and Spice O' Life. Determining which pitchers are Pyrex and which are made by Libbey is simple. Pyrex pitchers always have "Pyrex" printed on the side, and they are very thin and fragile, like laboratory glass. Libbey pitchers are thicker and more hefty.
Newer Coordinates patterns are too numerous to mention. Most patterns from the 1980s & 1990s include matching glassware, the majority having the distinctive single bulge shape near the base, but others have a thick heavy base and straight-sided shape. Libbey also made beverage jugs in selected patterns for the Corelle Coordinates line.
Some licensed Libbey glassware is marked with the word "Crisa". Crisa is a Mexico based subsidiary of Libbey Inc. Some, but not all of Libbey's products are marked with an "L" logo (shown at right). Canadian-made Libbey glasses are often marked with the Libbey St-Clair logo instead (shown at left).
Libbey glasses with a single bulge near the base.
James Bradley Assoc. (Glassmates):
Products from James Bradley Associates, of Northridge California, are easier to identify. Most items are marked with "1973 James Bradley Assoc Inc", but some are dated 1974. The brand was called Glassmates, but this name only appears on packaging. It seems that JBA was not a glassmaker at all, and was only in the business of decorating blank glassware manufactured by other companies.
Patterns imitated by JBA are: Butterfly Gold, Snowflake Blue, Spring Blossom Green, Old Town Blue, Woodland Brown and Spice O' Life. Glassware sets were offered in clear glass, as well as with a white exterior finish.
Beverage jugs also were available and they have a similar narrow-necked shape as those made of Pyrex. The difference is easily spotted though with the white exterior finish on JBA versions.
Also part of the Glassmates brand were pedestal mugs in white opal glass, with decorations imitating: Snowflake Blue, Butterfly Gold, Spring Blossom Green, Old Town Blue, Woodland Brown, April, Blue Heather, Indian Summer, Meadow, Spice O' Life. The mugs were manufactured by Federal Glass and a few have Federal's logo on the bottom, an "F" within a shield. But most mugs have no maker's mark at all, but their distinctive "B" shaped handle identifies them.
Besides glassware, JBA also put their name on vinyl placemats. So far only a "Butterfly Gold" version is known, bearing a 1972 date. The pattern is not very convincing and does not match the glassware designs that this company produced either.
From early 1986 to mid 1992 Indiana Glass held a licence from Corning to produce matching glassware under the "Drinkware for Corelle" brand.
One style of glass from this company is recognizable by a double bulge near the base. Known patterns include: Apricot Grove, Black Orchid, Blue Lily, Country Violets, First Of Spring, Forever Yours, Morning Blue, Silk & Roses, Symphony.
(Photo: Morning Blue with a double bulge near the base.)
After losing the Corning licence, Indiana launched the "Complements" brand based on look-alike patterns. Imitations of Forever Yours, English Breakfast, First of Spring and Apricot Grove exist with a double-bulge shape. There are other glass products, like candy dishes, decorated with this version of Forever Yours.
Another type from Indiana Glass has a slight hour-glass shape, narrowest in the middle and flared top and bottom, and the base is flat and thin. The patterns seem authentic, and known examples include: Butterfly Gold, Old Town Blue, Morning Blue, Ribbon Bouquet, Blue Floral, Blue Lily, Calico Rose.
(Photo: Morning Blue with an hour-glass shape.)
A slightly different style that might also be from Indiana Glass also has a similar thin flat base, but the sides are completely straight. This type exists in practically the same variety of patterns as the hour-glass shape.
This Canadian manufacturer made glasses with patterns matching Spice O' Life, Country Festival and Old Orchard. Glassware from this company is generally marked with a capital "D" logo.
Spice O' Life glasses have a look-alike pattern, and their shape is similar to Libbey's single bulge style, but the printed design is different and the French phrase is absent.
Glasses matching Old Orchard seem to be a perfect match, but it is unclear whether they are a licensed product.
(Photo: Old Orchard glasses.)
A version of Country Festival was produced with glasses as well as tabletop accessories like salt & pepper sets.
Green tinted juice glasses from Dominion Glass. They might be meant for Spring Blossom Green.
Glasses matching Strawberry Sunday, Wildflower, Almond, Slate and Citrus, plus dark brown which was meant for Woodland Brown. Image from 1983 catalogue. Cinnamon was also available. Sizes are: 10½ oz, 12 oz, 16 oz. They are authentic licensed products, but the manufacturer is unknown.
Chrome Top Guide: Dominion Glass