"dadiOH" wrote in message

No, dog's nails don't scratch glass. The sharpness of the nails has
nothing
to do with it, only the relative hardness of the materials. Glass has a
Moh's hardness of around 7...many, many, many times harder than the
material
from which dog nails - and yours - are made. Can you scratch glass with
*your* fingernails? Not a chance...

Bull****. My small dog that does not pick up sand has scratched our glass
also. Your theory seems correct but in practice, dogs can scratch glass.
Just come to my house and I'll show you.
Ed