Want to Start Collecting Vintage Pyrex? Many of us likely remember some iconic piece of Pyrex glassware in a mom or grandma's kitchen. The avocado green casserole dishes in the "Spring Blossom" print and classic mixing bowls, sold in sets of primary colors, have held countless top-secret family recipes and decorated the dinner tables of multiple generations. Now, the timeless serving dishes are having a renaissance of sorts, thanks to a thriving secondary market powered by antique malls, intimate circles of collectors, and of course, eBay. Pyrex made its debut on the consumer market in 1915, when Corning Inc. revolutionized the at-home glassware market with the introduction of borosilicate glass. Thanks to the addition of boron trioxide, borosilicate glass is described as "low-expansion," which means it's less likely to explode in high-heat environments like a ripping hot oven. It's also less susceptible to thermal shock, or breakage that occurs in extreme temperature disparities. With the introduction of Pyrex, home cooks could now prep, cook, serve, and store their favorite dishes all in the same bowl.