It’s also available but much harder to find in pink butterprint and yellow butterprint.On the other end of the Pyrex-collecting spectrum is a young, twenty-something Pyrex enthusiast who calls herself Pyrex Hellcat.Pyrex Hellcat says she got into the hobby by way of the whole 1950s-muscle car-pinup scene.You can’t hang around estate sales for very long without eventually running into a piece of Pyrex; for example, a vintage Gooseberry 473 (if you want to get technical).While estate sales aren’t the only places to find vintage Pyrex, they’re a pretty good way to start your search, especially as the Baby Boomers begin to let go of their collections.They don’t want demand driving the value of Pyrex up. Pyrex hunting and collecting is fun and easy, if you know what to look out for. Pyrex was originally made out of borosilicate glass, which was created to use in science labs because it didn’t expand or contract with heat.(Collectors, whether they’re into Pyrex or Star Wars collectibles, are a lot like hipsters: territorial over their “thing,” whatever it is, and always in search of that next cool piece to add to their collection. In 1915, the glass was sold to Corning Glassware and branded under the new name “Pyrex” which was then used to create all sorts of kitchenware.It’s been popular ever since, even after the 1998 switch from borosilicate to the cheaper and even more thermal resistant tempered glass.When the clear-glass ovenware debuted in 1915, it was considered a boon to kitchens everywhere because now chefs (and housewives) could keep an eye on their food while it was cooking.By 1922, the Pyrex line featured 22 different pieces that served various purposes.But the colored vintage Pyrex bowls, which debuted in 1947 and lasted well into the 1980s are what collectors go crazy over.