Today, while exploring a new area and breaking some rocks I discovered that breaking rocks can permenantly damage weapons.
I was utterly shocked. There was no warning for this, and it quickly came to the point of adding a very serious penalty to my PC's weapon, which should honestly have NO problem from hitting rocks.
Also, I was given no indication that these rocks were bigger, stronger or thicker or more durable than any other rocks, furthering my frustration. While in theory, I think weapon damage is a nice touch, the fact that there was no way of knowing this would cause permenant damage made it extraordinarily frustrating.
My suggestion is to remove the damage penalty (but keep the unmentioned penalty if you know where I'm talking about), or make SURE that anyone who attempts to break the rocks is fully informed about the durability of the rocks and the likely effect it will have on weapons swung at it.