
I can quite see the possibility of it being a horn of some sort, but, in fact it is only one inch long.
Kris was correct. Well done. It is a claw, one of Penny's dew claws. I don't know whether all breeds of dog shed them. Penny does occasionally and so did Bobby the Lurcher. Only the second one I have found in the seven years she has been with me. Look closely and you will see the bottom end of the old claw is hollowed out. This is where the new claw was growing, partly inside the old one.
Thank you to all who had a go at guessing.
Here we go with a new close view

of what?
Please leave your guess in the comments.
They will be revealed, along with the answer, next Monday.