Ben Bunton Pyrex glassware used to be made of borosilicate glass,...
· Comment — Archer T. Ships replied to James Anderson's comment. · View on Facebook · Markdown source
Ben Bunton Pyrex glassware used to be made of borosilicate glass, which is resistant to thermal shock. Later, the owners of the Pyrex brand started making it out of soda-lime glass in some locations. So, depending on when/where his measuring cup was made, it might be made of soda-lime or it might be made of borosilicate.