soda-lime

Since when is glass (I assume we mean soda-lime glass) a separate phase of matter?

Pyrex(TM) used to be really tough low-expansion borosilicate glass, or perhaps properly tempered soda-lime glass, truly great stuff.

The whole point of Pyrex was resistance to heat, which you don't get with the cheaper soda-lime glass.

The only reliable test you can do at home is density (soda-lime 2.52, whereas borosilicate ~2.23, unit g/cm^3).

Pyrex was the brand for Corning's borosilicate glass products, which is an almost all-around superior substitute for regular soda-lime glass.

However, the company that purchased the cookware products switched to soda-lime glass, adopting the name pyrex (spelled with all lowercase letters).

With this in mind, they switched the cookware to soda-lime glass, a less expensive component.

Tempered soda-lime class is more resistant to breaking from rough handling than borosilicate, so there's a real tradeoff between the two.

At least I learned how to tell them apart (soda-lime has a blueish color, and borosilicate is clear).

Unfortunately not true; the Pyrex I've seen sold in Australia is soda-lime glass as well.

The maximum tolerated temperature change for soda-lime glass is only ~60C.

The article also mentions soda-lime Pyrex® products from the '30s.

I didn't really appreciate the weaknesses of modern soda-lime "pyrex" until I tried to use a baking dish to steam my oven for baking bread (normally I use a cast iron pan).

Soda-lime glass, now called pyrex, isn't as resistant to thermal shock, but it is durable enough for everyday cooking.

Soda-lime glass is just the everyday crap that beer bottles are made out.

Soda-lime glass has a greenish hue (look at it sideways).