What is the difference between Pyrex and quartz glass?
Pyrex is actually a trade name for Corning borosilicate glass, but is commonly used synonymously to refer to any borosilicate glass. Borosilicate is a silicate glass with boron in it. It has a very low coefficient of expansion compared to other glass. Quartz glass is a highly pure silicate glass with a coefficient of expansion even lower than borosilicate glass and an even higher melting point.