Bakelite
From Wiki
Bakelite is a popular term for describing the tiles in games like Hive, Trax, Tantrix, etc.
In December 2008 I got a comment that such tiles are not in fact Bakelite:
none of these games' tiles are made out of Bakelite. Some crazy switch has closed in the BGG collective consciousness to declare that "if it's a tile, and it's injection molded from plastic, it must be Bakelite!" This is just not the case. There are a million thermosetting plastic resins that aren't Bakelite.
Then I noticed on the website for Trax mention of "urea" plastic: http://www.traxgame.com/about_reviews.php?show=Reviews
Only the first 4,000 sets contained cardboard tiles, before the high quality urea plastic hand painted tiles were adopted as the standard TRAX tile.
So it seems that indeed "Bakelite" has come to be misused in a generic sense, like Kleenex, Xerox, etc.
