I personally never knew there was a difference. I knew Corning developed Pyrex brand cookware but didn’t know there were different types of Pyrex until a recent article I read. I thought I’d share with you.

PYREX (Uppercase/Vintage): Manufactured by Corning, this borosilicate glass is superior for oven-to-table use due to its high resistance to thermal shock. It is typically found in thrift stores or older sets.

pyrex (Lowercase/Modern): Produced by World Kitchen LLC (now Corelle Brands) since the late 1970s, this tempered soda-lime glass is designed for durability against breakage, but it is more susceptible to shattering if moved directly from a hot oven to a cold surface.

Identification: Look at the logo—all capital letters ("PYREX") indicates older, typically more heat-resistant glass, while lowercase ("pyrex") denotes newer tempered glass.

Uses: Both are safe for oven and microwave use, but experts advise avoiding rapid temperature changes (e.g., freezer to oven) with the modern lowercase pyrex to…