You need a magical enhancement bonus to sunder a magical weapon, and adamantine does not inherently possess such a bonus.
Magic Weapons and Shields
The attacker cannot damage a magic weapon or shield that has an enhancement bonus unless his own weapon has at least as high an enhancement bonus as the weapon or shield struck. Each +1 of enhancement bonus also adds 1 to the weapon's or shield's hardness and hit points. If a combatant's shield has a +2 enhancement bonus, a combatant add 2 to its hardness and to its hit points.
Caliban said:I disagree with the Sage about creatures with natural DR being able to sunder magical weapons. It's not a bad house rule, but I don't believe it's allowed with the core rules.
As for using an adamantite weapon to sunder, I don't see anything in the core rules that requires a magical enhancement bonus to sunder a magical weapon, so a natural enhancement bonus should do just as well.
Stalker0 said:
I'm wondering how old that sage reply is, because to my memory the distinction between natural and magical enhancement bonuses for things like adamantite didn't come out until MMII, which didn't come out all that long ago.
Magic Weapons and Shields
The attacker cannot damage a magic weapon or shield that has an enhancement bonus unless his own weapon has at least as high an enhancement bonus as the weapon or shield struck. Each +1 of enhancement bonus also adds 1 to the weapon's or shield's hardness and hit points. If a combatant's shield has a +2 enhancement bonus, a combatant add 2 to its hardness and to its hit points.