====== PYREX (vs. pyrex) ======

**PYREX** is historically the most famous brand of heat-resistant glass cookware, developed by Corning Glass Works in 1915. Originally created for railroad signal lanterns, the material (borosilicate) was adapted for the kitchen after a scientist's wife successfully baked a cake in a sawed-off battery jar.

===== 1. The Great Divide: UPPERCASE vs. lowercase =====
It is crucial for consumers to distinguish between the two versions of the brand today:

^ Brand Mark ^ Material ^ Region ^ Characteristics ^
| **PYREX** (All Caps) | **Borosilicate Glass** | Europe / Africa / Middle East | Extreme thermal shock resistance. Can go from freezer to oven. Distinctive blueish tint. |
| **pyrex** (Lower Case) | **Soda-Lime Glass** | USA / North America | Tempered glass. More resistant to dropping (impact) but **less resistant to thermal shock**. Can shatter if moved from cold to hot. |

===== 2. Laboratory Origins =====
The original formula was so robust that it became the standard for laboratory beakers and test tubes worldwide. This scientific pedigree is why vintage PYREX pieces are highly collectible and still functional after decades.

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**See Also:**
  * [[:en:materials:borosilicate_glass|Thermal Shock Explained]]
  * [[:en:materials:soda_lime_glass|Why US Pyrex Changed Formula]]

{{tag>brands usa glass pyrex history controversy}}