Item destruction

[Amnekian]

Just to be sure, for I am letting myself go off some basic resistances for, what may be, a misconception of my part.

How exactly does item destruction work? If I wear a Metal Shield of Fire, it says can be destroyed by acid. Does this mean that one unlucky shot and off goes my shield? Or does it mean it gets degraded with acid, getting those -3 to AC? Or does the item gets destroyed if it reaches a negative AC?

[Derakon]

Equipped items can never be destroyed outright; only items in the inventory or on the ground are so vulnerable. Yeah, this distinction makes no sense. Anyway, so if your shield is equipped, acid attacks can reduce its AC modifier all the way down to [5,-5], at which point it cannot be further damaged. If the shield is sitting in your inventory, then instead every acid attack has a small chance of destroying it outright. If it's on the ground, then any ball acid attack will destroy it, guaranteed. I'm pretty sure ray attacks don't affect items, even though they're also area-of-effect spells. Not that there are any acid rays in Vanilla.

[Amnekian]

Riiiight. Oh well, better to learn now than even later. Thanks!