Pyrex kitchenware was first introduced in 1915, and today, collectible vintage Pyrex items fall somewhere in the $30-$400 range. Pyrex dishes with the rare "Turquoise Diamond Pattern" produced from 1953 to 1960 regularly fetch as much as $600 per piece — but you may not know what makes these items so valuable.

When Pyrex debuted its containers, they were made of borosilicate, and when put under heat, this material only expands 33% as much as other commercial glasses do. Come the 1970s, the company switched to less durable soda-lime glass and began to label their products with “pyrex” in lowercase, rather than the uppercase “PYREX.”

While old Pyrex is much more durable and rare, and thus more valued than modern dishes, for some enthusiasts, it's all about nostalgia. Pyrex released 170 appealingly kitsch patterns from 1956 to 1983, each with a whimsical name like Golden Honeysuckle, Lucky in Love, Pineapple Party, Cloverberry, and Angelfish