My cat has a crust like formation on her fore paw central pad

[cathat]

It is round measuring 6mm in diameter and looks discolored.

It is circumscribed by a furrow and the area feels hard when touched.

The cat does not appear to be in any kind of pain, she does not even notice that thing on her paw.

We noticed this because she was making a sound when walking on wooden floors (we're not sure whether it is the "crust like formation" or her claw making that noise).

We are going to the vet tomorrow, but on previous occasion they have proved less than helpful, so this is why I'm asking you guys.

We read a lot of scary stuff on the net, and we're a bit spooked.

Has anyone seen anything like this?

Thanks for your time, really means a lot