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 these patterns too, plus Morning Blue. There are Meadow, Indian Summer, Wildflower, Strawberry Sunday, Country Festival and Spice O' Life glasses by Libbey too, but these designs seem to be look-alikes.
(Photo: Small Libbey glasses with a version of Wildflower.)
Libbey Glasses: This Butterfly Gold version has a coloured rim, and the Spice O' Life version is inscribed with "Bonne Sante".
There are also closed-handle pitchers, beverage jugs and cork-top storage jars that appear to be made by Libbey with look-alike designs. These include Butterfly Gold, Spring Blossom Green, Country Festival and Spice O' Life. Determining which pitchers are Pyrex and which are made by Libbey is fairly simple. Pyrex pitchers always have "Pyrex" printed on the side as part of the decoration, and they are very thin, lightweight and fragile, like laboratory glass. Conversely, 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).
The typical "single bulge" shape of many Libbey glasses.
James Bradley Assoc. (Glassmates):
Products from James Bradley Associates, of Northridge California, are easier to identify. Almost all of their pieces are marked with copyright "1973 James Bradley Assoc Inc", and some say 1974. The brand name was Glassmates, but this only appears on packaging. It is highly probable that JBA was only in the business of decorating blank glassware made by other companies.
Patterns imitated by this company are: Butterfly Gold, Snowflake Blue, Spring Blossom Green, Old Town Blue and Spice O' Life. Glassware sets were available 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 the JBA versions.
Also part of the Glassmates brand were pedestal mugs in white opal glass. They were available in the patterns listed above, plus Blue Heather and Indian Summer. The mugs were manufactured by Federal Glass and a few have Federal's logo on the bottom, an "F" within a shield. 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 has been noted, bearing a 1972 copyright date. The pattern is not very convincing and does not match the glassware patterns they 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 the "double bulge" near the bottom, and exists in the following patterns, but there might be more too:
First Of Spring
Silk & Roses
After losing the Corning licence, Indiana launched the "Complements" brand based on look-alike Corelle patterns. Imitations of Forever Yours, English Breakfast, First of Spring and Apricot Grove exist with the double-bulge style. There are other items, like candy dishes, made with this version of Forever Yours.
This Canadian manufacturer made glasses to go with Spice O' Life, Country Festival and Old Orchard. Glassware from this company is generally marked with a capital "D" logo.
(Photo: Old Orchard glasses.)
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 quite different from that of Libbey glasses and the French phrase is absent. The Country Festival version can be found on glasses as well as salt & pepper shakers. Glasses matching Old Orchard seem to be a perfect match, but it is unclear whether they are a licensed product.
Green tinted juice glasses from Dominion Glass. They might be meant for Spring Blossom Green.
There are some glassware shapes from unidentified makers that bear authentic looking patterns.
One notable style can be found in Butterfly Gold, Old Town Blue, Morning Blue, Ribbon Bouquet, Blue Floral and Blue Lily. It was made in two sizes and has a slight hour-glass shape, narrowest in the middle and flared top and bottom; the base is flat and thin. Another style that might be related also has a flat base but the sides are completely straight. This type has been seen in practically the same variety of patterns as above.
(Photo: Morning Blue with an hour-glass shape.)
A Woodland Brown pattern also exists on glassware. The design is printed on a white band near the top of the glass. This type might be from Libbey.
Glasses matching Strawberry Sunday, Wildflower, Almond, Slate and Citrus, plus dark brown which was meant for Woodland Brown. Cinnamon was also available. Sizes: 10½ oz, 12 oz, 16 oz. Image from 1983 catalogue.
Chrome Top Guide: Dominion Glass