Primary color nesting sets were launched in 1945.

"It IS clean .. you can SEE it's clean .. it's PYREX ware!"

Pyrex was introduced in 1915 by Corning Glass Works, originating from heat-resistant "Nonex" borosilicate glass developed in 1908. Inspired by Bessie Littleton (wife of Corning Glass Works physicist, Jesse Littleton) to bake a sponge cake after her traditional earthenware casserole dish shattered.  The cake baked, did not stick, and the glass did not shatter proving its effectiveness as bakeware. This invention led to the creation of the Pyrex line which launched in 1915 as the first brand of heat-resistant glass bakeware. The brand transformed durable laboratory and industrial glass into iconic kitchen bakeware, expanding from clear pie plates to colored opalware in the 1940s. 

In 1915, Pyrex was officially launched with the first line including 12 pieces sold at Jordan Marsh in Boston.  In 1920, the product line expanded to include teapots, coffeepots and nursing bottles.  In 1930, Pyrex introduced "Flameware" designed for direct stovetop use.  

Modern Usage:  While not typically used today, the concept directly correlates to modern "cake in a jar" techiques where cakes are baked or preserved in canning jars for gifts or long shelf life.  Baking cakes in jars involves pouring batter into canning jars (like Mason jars) and baking them at roughly 325-350 degrees.  Sealing them immediately upon removal from the oven creates a vacuum allowing the cake to stay fresh for 4-6 weeks.  This method is popular for portable, single-serve desserts, gift-giving or extended storage. 

Grease jars well, fill about 1/2 to 2/3 full.  Bake, then immedately apply hot lids and rings.  As the cake cools, the jar seals.  Pound cake, cheesecake and fruit-based cakes work well. for this method.  And straight-sided jars work best.

Vintage Phoenix Opalware Baking Dish

Special markings on Pyrex distinquish vintage borosilicate glass (pre-1998) from modern soda-lime glass* with uppercase "PYREX" indicating older, thermal-shock-resistant pieces while lowercase "pyrex" signifies newer, more sensitive glass.  Key markings include molded numbers (e.g., 502) or "Made in USA". 

*Soda-lime glass is the world's most common type of glass.  If you've ever sipped from a basic tumbler at a restaurant or opened a jar of pasta sauce, you've encountered it.  It's used in everything from window panes to soda bottles to inexpensive drinkware. 

The iconic measuring cup has been around since 1915. 

Pattern Pyrex names (1950s-1980s)

Retro Kitchen Wall Art

Some of the 33 patterns include Butterprint, Friendship, Spring Blosssom, Daisy, Terra, Diamonds, Balloons, Black Snowflake, Horizon Blue, Butterfly Gold, New Dots, Colonial Mist, Gooseberry, Eyes, Woodland and Square Flowers.