"Good Pyrex" is generally defined as vintage or European-made Pyrex crafted from highly durable, temperature-resistant borosilicate glass. The most reliable way to identify this type is to examine the logo: uppercase "PYREX" indicates the stronger, older borosilicate glass, while lowercase "pyrex" indicates newer, tempered soda-lime glass.
The most sought-after vintage Pyrex patterns are driven by color, scarcity, and mid-century aesthetics. Highly coveted designs feature rare promotional motifs (like "Lucky in Love" or "Atomic Eyes") and vibrant, iconic colorways (such as Pink Gooseberry, Butterprint, and New Dots).
There are two different types of Pyrex: vintage PYREX (all uppercase) and modern pyrex (all lowercase). They feature different compositions, handle heat differently, and are sold in distinct regions.
The easiest way to tell if your Pyrex is vintage is to check the logo on the bottom: all-caps "PYREX" indicates a vintage piece (made by Corning before the late 1970s), while lowercase "pyrex" generally indicates modern, newer production.
Vintage Pyrex is highly sought after by collectors and mid-century design enthusiasts, with specific sets and rare promotional items fetching anywhere from a few hundred to thousands of dollars. Rarity, pristine condition, and whether a piece was sold as a limited-edition promotion heavily drive its value.
One of the most valuable vintage Pyrex pieces you can find is the Atomic Starburst casserole dish. Only manufactured for a year beginning in 1960, it was one of the brand's promotional pieces Wright shares are highly sought after due to their limited production.
Numbers on the bottom of vintage Pyrex dishes are product identification codes indicating the mold size and model type. These 3 or 4-digit numbers allow collectors to identify specific bowls, casseroles, or lids, often with the last digit denoting capacity in pints or quarts (e.g., 401 = 1.5-pint bowl).
To date Pyrex, flip the piece over and examine the backstamp, logo, and inventory numbers. The branding, material, and shape offer the clearest clues to determine when a piece was manufactured.
The most valuable vintage and antique glassware ranges from 19th-century French crystal sets and museum-quality Art Nouveau vases to highly specialized, mid-century American studio pieces.
Pyrex can last a long time. If you have Pyrex that's still in good condition (i.e., no cracks or chips in the glass), don't throw it away. Give it away or donate it to a thrift shop.
The "good" Pyrex is vintage glassware featuring the uppercase PYREX logo. Made from borosilicate glass, it can handle extreme temperature changes (thermal shock). Modern glassware has a lowercase pyrex logo. Made of tempered soda-lime glass, it is more prone to shattering from sudden temperature shifts.
Old Pyrex (vintage) is primarily made of borosilicate glass, which is highly resistant to extreme temperature shifts. New Pyrex is made of soda-lime glass. While new soda-lime glass is highly resistant to dropping, it is more likely to shatter from thermal shock than older borosilicate glass.
Both versions are "real" Pyrex, but they are made from entirely different materials with different heat tolerances. The easiest way to identify which type you have is to look at the logo on the bottom or side of the dish.
Patterned Pyrex, like the 1956 Pink Daisy or 1957 Butterprint, is highly collectible and can be worth hundreds of dollars depending on condition. Authentic Pyrex pieces can often be identified by their back stamps, which were used between 1915 and 1965, or by unique characteristics like yellowish or blue-tinted glass.
The Lucky In Love design is printed on the one-quart Round Casserole (473) and remains one of the most elusive Pyrex designs ever created by Corning Glass Works. Released in 1959, Lucky In Love is most likely a limited release product or even a test piece.
Vintage Pyrex manufactured before the 1980s frequently contains high levels of lead in the exterior colored paint. The clear, unpainted, or tinted borosilicate glass itself is generally considered lead-free, but the exterior decorative patterns and colored coatings often test positive for lead.
Many people collect ruby glass pieces and pay high prices for the rare ruby glass examples. Ruby glass is presented and made into famous ruby glass cut to clear vases, ruby glass bowls, drinking glasses and goblets, and many other types of glass forms.
Right now, the most highly sought-after collectibles are driven by 90s/2000s nostalgia, rarity, and playable art. Top categories include:
The Seven Ultra Rare Sea Glass Colors
The rarest and most valuable vintage Pyrex piece is generally considered to be the "Lucky in Love" 1-quart casserole dish, dating back to 1959.
Use barkeepers friend liquid, it is not so abrasive. Bon Ami, or Bar Keepers Friend. I've cleaned my Pyrex with it many times. Magic eraser!
The naming of these new pieces as "Cinderella" likely had much to do with the popularity of the Cinderella story current at the time both in film and on Broadway. Corning marketers also hoped the underlying theme of a coveted glass object would have a subliminal effect on consumers.
To tell the difference between highly durable, heat-resistant Pyrex and modern versions, check the logo on the bottom. Vintage pieces with an all-caps "PYREX" are made of superior borosilicate glass, whereas modern pieces with a lowercase "pyrex" are made of tempered soda-lime glass that is more prone to shattering from sudden temperature changes.
Plastic #5 - PP (Polypropylene)
Used in production of most yogurt containers, some pancake syrup bottles, and bottle caps. Can be recycled into plastic lumber, bins, car battery cases, brooms, and ice scrapers.
To date Pyrex, flip the piece over and examine the backstamp, logo, and inventory numbers. The branding, material, and shape offer the clearest clues to determine when a piece was manufactured.