Averages are for Corvallis Municipal, which is 5 miles from Corvallis.
Warnings. Do not use pumice stones to clean marble, laminate, plastic or fiberglass toilets; doing so will result in permanent scratches. A dry pumice stone will also scratch porcelain, so be sure to keep the stone and the toilet surface wet at all times.lean With a Pumice Stone. Before cleaning a porcelain toilet with a pumice stone, you must thoroughly wet both the stone and the surface to be cleaned and keep the stone and the surface wet as you work.
Quartz is so hard that it will easily make a deep scratch in glass. Even if you press hard, a meteorite will at best only make a weak scratch mark. In the photo above, the top scratch was made with a quartz crystal. The next mark was made with a piece of chert, which is another form of quartz.