4 ms·

Unfortunately, modern Pyrex contains no borosilicate but is now made from "tempered soda-lime": http://en.wikipedia.org/wiki/Pyrex http://en.wikipedia.org/wiki/

• code_duck 16y ago
  That only refers to Pyrex cookware, not lab or glassblowing glass. Historically, Pyrex was a brand of borosilicate labware, glassblowing supplies and cookware, but the cookware brand was spun off by Corning in the 90s. They started making Pyrex brand glassblowing glass in China, and it's still borosilicate (it makes a huge difference for scientific glass blowing!).