As long as the cat's nails have a lower Mohs hardness [1], they won't scratch the screen. In this case, glass has a mohs hardness of about 5.5, and karatin (wha

As long as the cat's nails have a lower Mohs hardness [1], they won't scratch the screen. In this case, glass has a mohs hardness of about 5.5, and karatin (what nails are made out of) is about 2.5. [1] http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness