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Unusual Pyrex

It doesn't take long for the determined Pyrex collector to become reasonably familiar with the Standard and Non-Standard patterns which were offered through the normal retail channels. Every so often, however, a piece will pop up that defies identification or explanation.

Collector guide books published in the past on the subject of Pyrex collecting were not familiar with some of the things taken for granted today. Even as little as five years ago, there were pieces classified as "unknowns" for which concrete information is presently available.

It is important to differentiate, however, between "rare" and "unusual". It may sound odd to say, but a piece may be rare but not necessarily unusual, examples being the 1959 promotional "Lucky In Love" casserole or the "turquoise diamonds" 403 produced for a third party. Their provenance can be traced and is documented.

The rare-but-not-unusual may also take the form of standard patterns in standard colors seen on shapes not offered as part of regular production. Such items may have had limited distribution in test markets. Examples include 024 round casseroles in the Butterfly Gold and Spring Blossom Green patterns, not seen in Pyrex dealer catalogs.

Many of the truly unusual are in the form of pieces whose base or decoration color deviates from the norm. These include an Early American Cinderella casserole in turquoise, or a Woodland or Daisy Cinderella bowl in green instead of the usual brown or orange. Note that all could be achieved by simply placing an as-yet undecorated bowl from one pattern on the decoration application line of another pattern.

The case of an unusual color decoration on a standard color bowl would have required a different scenario. Since the screen printing process was automated, the paint color on the bowl's normal decoration line would have to have been changed. This also suggests such pieces would not necessarily be one-offs, but rather produced in at least a small batch. This scenario is more likely to be the result of a management-sanctioned product test run.

More unusual is a pattern decoration seen on a dish shape other than regular production, like a Turquoise Snowflake oblong casserole. Or an applied decoration in a non-standard color. Both these scenarios require more effort than the previous examples, including special screens made to accomodate the dish shape or the replacement of the paint color in the automated decorating process.

Most unusual by far are pieces with non-production patterns applied to dishes in non-production base colors. These would have to have been product test samples which under normal circumstances would have been destroyed, or at least were not intended to have left the factory. Apparently, there was quite a bit of experimentation going on either at Corning or at the opalware plant, and many unofficial pieces were produced over the years.

Additionally, extremely rare cases include shapes that were not regular production, such as a divided 033 oblong casserole and a Cinderella bowl smaller than a 441 numbered 440.

Whether they be marketing test pieces, production errors, or just some unauthorized employee lunch-hour creations is to varying degrees unclear, but many have "escaped into the wild" and are sought after by collectors.

Other unusual sightings include:

  • Cloverberry 475 Cinderella casserole in turquoise with gold leaf "cloverberry" pattern
  • "Hex Signs" 475 Cinderella casserole in white with gold leaf pattern and patterned clear lid
  • "Hex Signs" 475 Cinderella casserole in white with turquoise pattern, patterned clear lid and patterned underplate
  • "Sunflower" pattern in orange-yellow on 473 and 503 opal
  • "Sunflower" pattern in white on turquoise 441 and 442
  • "Compass" pattern in white on turquoise 033 oblong casserole
  • 440 series bowls in "Blue Dianthus" pattern in cornflower blue on opal and the reverse
  • "Barcode" 470 series casseroles in colors other than light blue on medium blue
  • Lucky In Love pattern on a Cinderella 475 2-1/2 qt. casserole
  • Verde Floral pattern in blue on 440 series Cinderella bowl
  • Oblong 4-quart casserole in turquoise with white "compass" pattern
  • Friendship pattern on yellow 441, blue 401, or green 402
  • Gooseberry 440 set in all opal with black pattern*
  • Gooseberry Cinderella 440 set in alternating yellow on opal and white on yellow
  • Gooseberry Cinderella 440 set in gold on ivory*
  • Butterprint 470 set in all opal with pink pattern*
  • 575 Space Saver in turquoise with gold leaf birds pattern
  • Oval casserole in opal with blue and gray "atomic stars" pattern
  • 043 oval casserole in yellow with gold "New Mexico" pattern
  • Starburst 575 Space Saver casserole in black
  • 575 Space Saver casserole in opal with blue clouds and stars pattern
  • Gourmet Cinderella 475 casseroles in black on opal and gold leaf on golden yellow
  • Golden Acorn pattern on ivory Cinderella 480 set
  • Turquoise on white Butterprint 548 Space Saver casserole
  • 035 oblong casserole in sage green with white scroll pattern
  • Pink Daisy 474 Cinderella casserole
  • Turquoise on opal 053 open baker with 7 large snowflakes per side

Other than * which may have been limited availability, all appear to be non-regular production US made Pyrex.

One interesting example is that of a 400 bowl set known as a "Red & Orange" set. Its colors are alternating solid shades of a burnt orange and a rust red. Examples found as NOS were in plain cartons marked only "400 CRS". The 400 obviously refers to the set's catalog number, but the CRS has been a bit of a puzzle. Since one example was found with a price sticker from the Corning Glass Center retail store, it might be surmised that CRS stands for "Corning Retail Store".

In April of 2017, with the assistance of collector and Instagram user "tosasfield3", it was determined that the shades of orange and red, the former having previously been identified as a match to the orange Daisy pattern collection 404, were also a match to the base colors, and in sequence, of the 1974-1976 Flameglo 400 series bowls. Was the CRS set-- by its style of backstamps necessarily produced 1975-1978-- a product test? Or was it merely a way to dispose of partially finished inventory from a discontinued FlameGlo pattern? We may never know for certain.

There are several patterns on rare and unusual pieces which did not appear on any standard production dishes or bowls. As with the promotionals that were not given official names, collectors have found it necessary to make up names for them. Included are monikers like Golden Gate, Golden Thistle, Amoeba, Cloverberry, Gypsy Caravan, Celestial, and Sunflowers.

Perhaps one clue to why and how these kinds of pieces came to exist lies in their propensity to be found in the Northeast US, in and around the environs of Corning, NY, and of Charleroi, PA, home to the Pyrex opal ware plant. These locales are also-- expectedly-- the prime sources of special company commemorative pieces.

Some collectors have made a mission of seeking out these Pyrex unicorns. At the 54th Annual Seminar On Glass hosted by the Corning Museum Of Glass in October 2015, many unusual and hard to find Pyrex pieces from her collection and those of others were highlighted by author Megan McGrady in her presentation for the Collectors Panel. Many more are featured in her book "The Hot For Pyrex Guide to Rare and Hard to Find Vintage Pyrex".

Decoration Mysteries

While there is a known and extremely rare example of Pyrex covered butter dish upon which the position of the farmer and the wife are reversed, the phenomenon is also seen occasionally on Butterprint Cinderella 441 bowls and 403 round nesting bowls. The farmer is normally depicted to the left of the wife.

That the printing screen could be reversed on the bowls is plausible; how the butter dish pattern came to differ is uncertain, as its decoration is not symmetrical. If seeking to acquire such "reverse" bowls, make certain they are pictured alongside standard examples or other points of reference like printing. Otherwise, it may simply be that the photo image is flipped.

Some Pink Gooseberry 472 and 473 Cinderella Round Casseroles are seen with their decoration rotated 180° from others.

Not Necessarily Rare or Unusual

For some pieces found in seemingly unusual colors, the answer lay in how several open stock bowls or limited run specials were marketed. It was not uncommon for both these types of products to be issued in colors opposite those of the same size bowls or casseroles included in alternating-color sets of their patterns.

  • Open stock bowls in colors opposite those sold with sets include the Autumn Harvest 401 and 403 (both rust), and Colonial Mist 402 and 404 (both dark blue).
  • More than one Cinderella 474 1-1/2qt. round casserole was offered individually in the color of its 475 2-1/2qt. sibling as a catalog number 484 set. These include Autumn Harvest, Butterfly Gold '79, Spring Blossom Green '79, and Woodland.
  • Standard Verde and Town & Country Cinderella round casseroles each have the 473 1qt. in two different colors. This was done so that their 470 and 480 sets could both have identical color sequences.
  • For others, the explanation was simply a pattern variation marketed through a non-traditional source. Two examples include the Verde Floral and the Orange Butterprint patterns, both having been identified as obtainable via trading stamp redemption programs like S&H Green Stamps.


On the other hand, a piece may be unusual but not necessarily a rarity. Sometimes, online sellers will try to make something not all that unusual or easily explainable out to be "rare" or "mismarked".

One is a "backwards backstamp". Occasionally, you'll encounter an opalware piece on which the backstamp is a reversed, a mirror image. Clear glass Pyrex such as pie plates were molded in such a a way that the backstamp was legible from the top of the piece. It appears that sometimes opalware may have been pressed on lines set up to do clearware. The opalware pieces seen with the characteristic appear to always be those with clearware counterparts. Alternately, since the backstamp is on a slug or die separate from the rest of the mold, it is possible clearware slugs may have inadvertently been placed in opalware molding line molds, although that scenario seems unlikely. In any case, hundreds if not thousands of pieces would have been so-created during the automated molding line runs, so it's not feasible such pieces are one-off errors.

Another would be 063 oval divided casseroles. At some point, the capacity was arbitrarily changed from 1-1/2 qt to 1 qt. but with no physical change to the dish. Since for most of its production life, the 063 was either not marked as to model number or capacity (or both), pieces marked 1 qt. are relatively fewer in number. Again, 063s so-marked cannot possibly be mismarked or production errors.

Non-USA Pyrex

For other patterns seen offered as rare and unusual, the answer is sometimes as simple as the pieces having been produced by Pyrex licensees in England, Australia, New Zealand or elsewhere, in patterns never distributed in the USA.

Pieces produced by Corning licensee Rigopal Argentina (Cristalerías Rigolleau, S.A.) are remarkable for their use of Snowflake, Gooseberry and Butterprint designs both in colors and on shapes other than those found anywhere else.

Notable among Rigopal pieces are Dots patterned 400 series bowls in a color sequence different from the US counterparts. Pink Butterprint on opal Cinderella 440 series bowls also exist.

Fabricated Rarities

Less experienced collectors should be aware that there are some instances where what appears to be a rare or unusual piece is not what it might seem.

The first is a practice employed by some to salvage badly dishwasher-damaged pieces. It involves the use of a permanent marker to revive the worn decoration. Some of these "restorations" can be quite convincing if one is not familiar with the technique.

The other is the use of custom made decals to create fantasy pieces. Examples would be a standard decoration in a non-standard color, a non-Pyrex pattern, or a standard pattern used in a non-original way.