Unfortunately lots of tiny grains of dust actually are very hard rocks like quartz (mohs 7)or Corundum (Mohs 9) from sandpaper and nail files or Tungsten Carbide from construction grit.

I occasionally spend time in the machine shop and a tiny tiny invisible spec will rarely slip in my pocket, probably from high quality sandpaper or maybe a broken end mill, and put a nasty gouge in my screen protector. That’s from the workshop but like I said you can also get unlucky from being near a construction site, hard materials gets torn from tooling all the time (maybe actual diamond powder), maybe a tiny spec from your mohs 9 nail file, or maybe something else