For all the discussion about Pyrex manufacturing below, here's a quick helper-
The original (and good quality glass) is sold as PYREX.
The worse glass is sold as pyrex.
Those 2 are licensed out separately.
The original (and good quality glass) is sold as PYREX.
The worse glass is sold as pyrex.
Those 2 are licensed out separately.
From the EU Pyrex webpage, when they talk about their materials in the French factory, they say it's borosilicate:
The Pyrex® glass is unique. It is a borosilicate glass that is tempered, of superior quality and has a great thermal and mechanical shock resistance. [...] The Pyrex® glass is made of pure sand (80%), soda (4%), Alumina (2,5%) and bore (13%).
PD: Following the life of Pyrex, Duralex and Saint-Gobain is quite a thing...