There are a couple of possibilities for China (which has never counterfeited anything, right? ) 'Pyrex' in this case (as in the case of heat-resistant glass made elsewhere) may be a genericized trademark (e.g. kodak, kleenex, xerox, zipper, aspirin, et al), and just be synonymous with borosilicate or heat-resistant glass.

Shattering pyrex To Show A Massive Weakness In Trademark Law

'Australian Pyrex' isn't PYREX® or Pyrex®; it's Australian Pyrex—not the same. Same for Crown Pyrex. I don't deny there could be confusion, but I don't know enough about the (legal) histories of the trademark & various corporate interplays to comment. That said, Australian Pyrex et al were/are to my knowledge not part of the urban myth.

My point is that the urban myth regarding the Chinese owning the PYREX® or Pyrex® trademarks, PYREX® or Pyrex® being made in China and no longer made in the U.S., and the change from borosilicate glass to tempered soda-lime glass being recent and/or for profit sake—has been debunked. Those claims are not factual.

Doc