Pyrex has been making glassware and kitchenware since 1915, and vintage Pyrex products have increased in value, especially with Pyrex switching from using borosilicate glass to soda-lime glass in kitchenware products in 1998.
The color and pattern can both help determine whether a Pyrex piece is antique or vintage, as well as the glass markings, stamps, and logos on the pieces themselves. The oldest pieces have Pyrex in all capital letters inside a circle with a “CG” for “Corning Glassworks,” the company name. If the word “PYREX” is capitalized with other words circling it. The circle logo ended in the 1960s.
Below are some tips you can use to help determine whether your Pyrex is vintage or made relatively recently.
Determining the Type of Glass
For glassware products, Pyrex pieces can be identified by the type of glass used. Pyrex in America changed the type of glass they use in 1998, so its glass products can be categorized by pre-and post-1998 pieces. The European Pyrex still uses borosilicate glass.
Types of Glass used by Pyrex in the USA:
Borosilicate Glass – The type of glass used by Pyrex before 1998, has no color to it. This type of glass is thermal shock resistant and very durable to withstand high temperatures and temperature changes.
Soda-Lime Glass – This type of glass has been used by Pyrex since 1998 and has a bluish-green hue to it. This is easily distinguishable from borosilicate glass, which has no color to it. This type of glass is not as heat resistant as borosilicate, which generated some controversy when the company began producing kitchen products made from soda-lime silicate only.
For glassware products by Pyrex, this is the first method you should use to determine when the piece was made as it will narrow it down to a general pre- or post-1998, after which you can use other methods to determine more precise production dates.
Patterns and Color
For other kitchenware products, an additional way to determine whether Pyrex is vintage is by looking at the color and pattern of the piece. Pyrex pieces from 1915 until mid-1940 were originally clear glass, and it wasn’t until later that colored and patterned bowls and casserole dishes were produced. These color pieces are quite popular with collectors today.
The first colors released by Pyrex were pastel shades of blue, green, and pink. From 1945 to 1950, they produced sets in the primary colors of red, yellow, blue, and green.
Along with colors, kitchenware with patterns was also introduced in the 1950s. The following patterns are some of the most popular:
- Butterprint: Image of farm scenes with roosters and farm figures. Produced from the late 1950s to the late 1960s
- Gooseberry: Images of berries on vines with leaves produced from the late 1950s-1960s
- Town and Country: Abstract star designs from the 1960s
- New Dot: Large colorful dots from the late 1960s
- Friendship: Orange and yellow roosters from the 1960s
- Butterfly Gold: Floral patterns from the 1970s
- Autumn Wheat: Sheaves of wheat from the 80s
- Snowflake: This pattern is found both in white on blue and white on black and were produced from the mid 1950s to the late 1960s
The images on vintage Pyrex can be found on Google so you can familiarize yourself with them. If you become familiar with these patterns, you will be able to identify whether your Pyrex is vintage based on the particular designs decorating the sides of it.
Check out our Vintage Pyrex Pattern and Color Guide for more information.
Markings, Stamps, and Numbers
If your Pyrex does not have any patterns or designs featured on it, have no fear as there are still other ways that you can identify whether the kitchenware is vintage. You can look at the glass markings, stamps, and logos on your Pyrex to determine when the piece was produced.
The oldest pieces have “PYREX” in all capital letters inside a circle with a “CG” that stands for Corning Glassworks. Some of the early stamps also have an image of a small figure blowing glass visible inside the logo’s circle.
In the mid-1950s, the company added: “Made in the U.S.A.” in all capital letters to the stamp. They also added a trademark symbol and trademark wording. The circle around the wording was replaced with straight lines in the 1960s, but these pieces are still considered vintage today.
If the Pyrex piece you are looking at is a casserole dish or bowl, it will also have an inventory number included on the stamp. If you know the inventory number, this will help you determine when the piece was made. In addition to the inventory number, pieces made after the 1970s may include other information such as a “no broiling” stamp. All of these clues will help you determine the date of the Pyrex and if it is a vintage piece.
Dating Pyrex Flameware
In 1936, Pyrex introduced Flameware. This type of product was called Flameware to communicate that it could withstand high heat and be used on top of the stove over a flame. Flameware percolators can be dated by their lid knobs — thinner knobs are older.
Qualities of New Pyrex
Newer Pyrex products are easily distinguishable because most of them have a modern aesthetic, pattern, or overall quality to them that sets them apart from the older, vintage pieces produced by the company. It is not uncommon for modern Pyrex products to have Mickey Mouse, Hello Kitty, or Star Wars designs printed on the side of them.
On top of modern image designs, the products themselves might have a more up-to-date design and features. In modern Pyrex pieces, you might see divisions in the glass so you can separate two different types of food in the same dish, or lids with leakproof snap-on sides for extra security. Common lid colors for the glassware are reds, blues, and greens. The glass also has the bluish tint from the soda-lime glass. All of these factors can help you quickly figure out the approximate date of your Pyrex.
Ask a Professional
When in doubt, you can always take your Pyrex to a professional. You can go to an antique store, a consignment shop, or a professional who specializes in Pyrex for help identifying a piece. You can also ask older family members or friends who are familiar with Pyrex, as they might remember the piece and what decade it’s from.
Vintage Pyrex is popular because it makes people feel nostalgic. Many people who own vintage Pyrex inherited it from a parent or grandparent, and it brings up fond memories of cooking in the kitchen.