Reference · Kitchen glass
How do you date a piece of Pyrex?
Logo case, then pattern, then shape. A three-pass dating method built only from records we read ourselves, with the patterns we could not verify left deliberately out.
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Date a piece of Pyrex in three passes. First the logo: uppercase PYREX is laboratory glass, lowercase pyrex is kitchenware and was introduced in 1975. Second the pattern, which usually narrows the window to under a decade — Pink Daisy 1956 to 1962, Butterprint 1957 to 1968, Gooseberry 1957 to 1966, Early American 1962 to 1971. Third the shape: a spouted, handled Cinderella bowl cannot predate 1957.
Pass one: the logo
Two marks exist and they are two different products, not two eras of one product. Uppercase PYREX is the laboratory line, historically borosilicate, made by Corning. Lowercase pyrex is the kitchenware line; the lowercase mark was introduced in 1975 and US kitchenware has carried it since.
So a kitchen piece with a lowercase mark is 1975 or later. A kitchen piece with an older uppercase kitchenware mark predates it. And a laboratory beaker with an uppercase mark is not a vintage kitchen find however old it looks — a point worth making because laboratory glass turns up constantly in searches for vintage Pyrex, priced under $10.
Pass two: the pattern
Printed opal-ware patterns are the tightest dating evidence available, because each ran for a known span. These four are taken from the museum record rather than from collector folklore.
| Pattern | Manufactured | What it looks like | Notes |
|---|---|---|---|
| Pink Daisy | 1956 to 1962 | Pink daisies on white | With Snowflake, the first patterned opal ware, using a new screen-printing process. Debuted on oval Decorator Casseroles in 1956. |
| Butterprint | 1957 to 1968 | Amish farmer and wife, rooster, wheat, corn | Turquoise on white and white on turquoise. Part of the Turquoise line released in 1963. |
| Gooseberry | 1957 to 1966 | Berries and leaves, no figures | Issued pink on white, white on pink, black on yellow, black on white, and a promotional gold on beige. |
| Early American | 1962 to 1971 | Colonial brown with 22-karat gold | The first Pyrex pattern printed in gold, and one of the longest running. Sold as Early Canadian in Canada. |
Source: the Corning Museum of Glass Pyrex pattern library, read 2 September 2026. Only patterns we read directly are listed; we have not reprinted date ranges we could not check.
Two of these overlap almost exactly, which is why Butterprint and Gooseberry are the pair most often mixed up. The separation is simple: figures mean Butterprint, fruit means Gooseberry.
Pass three: the shape
- Cinderella bowls — nested mixing bowls with a pouring spout on one side and a handle on the other, designed by John Philip Johnson — were introduced in 1957 carrying Butterprint and Gooseberry. A Cinderella bowl therefore cannot be older than 1957.
- Decorator Casseroles, oval with a clear cover, arrived in 1956 with Pink Daisy. The clear cover was marketed as a trivet and an extra serving dish as well as a lid.
- Space-Saver Casseroles, square, followed in 1957.
- Divided and open bakers, oval, followed in 1958.
- Set numbers help. Butterprint’s 470 Bake, Serve and Store and 500 Oven Refrigerator and Freezer sets are 1959; its 480 casserole set is 1960.
The glass itself, and why it changed
Original Pyrex was borosilicate, which resists thermal shock well. Corning moved US kitchenware toward tempered soda-lime glass for manufacturing cost reasons, and all American-made kitchen Pyrex since 1998 is soda-lime carrying the lowercase logo.
The practical reading for a buyer: a piece being old does not make it better in the oven, and a piece being new does not make it worse. Both materials fail under thermal shock. Do not put either on a cold surface straight from a hot oven.
Who made it, and when
| Period | Owner or maker |
|---|---|
| 1915 onward | Corning, as a consumer products division |
| 1998 | Corning spins the division off; sold to Borden Food Corporation |
| 2000 | Renamed World Kitchen, required to drop the Corning name |
| 2002 | Chapter 11 filing and reorganisation |
| 2018 | Renamed Corelle Brands |
| 2019 to 2021 | Merger with Instant Brands; parent renamed Instant Brands |
| 2023 | Instant Brands files Chapter 11 |
| 2024 | Centre Lane Partners transfers Corelle Brands to Anchor Hocking |
| April 2025 | Charleroi, Pennsylvania plant closes permanently after 132 years; production moves to Lancaster, Ohio |
Source: Corelle Brands and Pyrex, read 2 September 2026.
Last verified 2 September 2026 against the Corning Museum of Glass pattern records for Pink Daisy, Butterprint, Gooseberry and Early American, and the published ownership and manufacturing history, all read on that date
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Where this method stops working
Frequently asked
How do you date a piece of Pyrex?
Three things in order: the case of the logo, the pattern, and the shape. Uppercase PYREX is the laboratory line; lowercase pyrex, introduced in 1975, is the kitchenware line. The pattern then narrows the window to a few years, and the bowl shape confirms it.
When did Pyrex patterns start?
Printed patterns on opal ware began in 1956 with Snowflake and Pink Daisy, using a new screen-printing process. Butterprint and Gooseberry followed in 1957.
What are Cinderella bowls?
Nesting mixing bowls with a spout on one side and a handle on the other, designed by John Philip Johnson. They were introduced in 1957 carrying Butterprint and Gooseberry, so a Cinderella bowl cannot predate 1957.
Is old Pyrex borosilicate glass?
Early Pyrex was. Corning began moving US kitchenware to tempered soda-lime glass for cost reasons, and all American-made kitchen Pyrex since 1998 is soda-lime with the lowercase logo.
Who makes Pyrex now?
Anchor Hocking. It received Corelle Brands from Centre Lane Partners in 2024, closed the 132-year-old Charleroi, Pennsylvania plant permanently in April 2025, and moved production to Lancaster, Ohio.
Sources and scope
- Pattern dates, shapes, set numbers and designer attributions: the Corning Museum of Glass Pyrex pattern library, read 2 September 2026.
- Glass composition, logo case and manufacturing history: Pyrex and Corelle Brands.
- Images: Wikimedia Commons, licences given in the captions.
- No price appears on this page; it is a dating reference.
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How this guide was made. We research and draft these guides with AI, then a person checks every price, link and factual claim against the source before it publishes. We work this way because it lets us re-verify prices across hundreds of guides in a day, which is what keeps the numbers here current; it does not decide what we recommend. Anything we could not verify is labelled as unverified rather than filled in.