I was thinking about how quartz is piezoelectric, and then I thought about how everyone wants a NOTE element (plays sound). So, in short, qrtz acts normal. When you go into the settings and check the 'Tone' checkbox, the qrtz plays a tone relative to it's tmp (yes, I know that it uses tmp for it's color variations) whenever it receives a spark. Of course, this could get relatively annoying, so I think that the Tone setting should be off by default. Keep in mind that qrtz will keep all of it's previous reactions and properties, so it will not break any saves (it will, however make any save using qrtz intothe most horrible noise in the history of mankind).
Could easily be remedied by making it default to off. Then, if someone's save needs it, they can put in a sign that says to turn it on. Much like people do now with Newtonian gravity, water equalization, and ambient heat.
EDIT:
could also have limits, such as 30-4000. If tmp(2) is less than 30 or more than 4000, it'll do nothing. This would also make it such that the auto-generated tmp qrtz makes no sound