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.