You could give it some slashing/piercing resistance. But I'd argue that is too much. Hardness 7 will make destroying the thing already pretty difficult.
And unless this happens during a combat encounter/ some kind of time crunch, it really doesn't matter at all. It will just take longer.
I wouldn't even let the players make the rolls, just decide it takes X minutes and move on.
You could give it some slashing/piercing resistance. But I'd argue that is too much. Hardness 7 will make destroying the thing already pretty difficult. And unless this happens during a combat encounter/ some kind of time crunch, it really doesn't matter at all. It will just take longer. I wouldn't even let the players make the rolls, just decide it takes X minutes and move on.