Destroying Magical Items (DMG)

Occasionally characters may find it desirable, useful, or vitally necessary to bring about the destruction of a magical item. Magical items are more resistant than ordinary ones, but they are hardly indestructible, as Table 29 shows.
Characters who have possession of a device and are determined to destroy it can do so at will. They need only snap the blade of a magical sword or burn a lock or whatever.
It is possible to target specific magical items held by others, but it is very difficult. (In fact, it is no easier or harder than attacking a non-magical item.) Attempting to destroy an enemy's magical item may require attack rolls, saving throws, and item saving throws.
The breaking of a magical item should result in something more dramatic than the breaking of a vase or a windowpane. As DM you are perfectly justified in describing a dramatic explosion of force, a small whirlwind, a foul stench, or whatever seems most appropriate to the moment.
For some items, particularly some staves, there are specific rules that define the effects of the item's destruction. Such cases are rare and the effects are devastating, so they are recommended only for those in the area. You might, for example, dictate that characters within 1 foot, 5 feet, or even 10 feet suffer 1d8 points of damage.
This is just an example—the actual damage can vary, at your discretion. Remember, however, that such damage should only be used for effect; it should never kill or seriously injure a character. After all, killing the character in the explosion of his own magical sword is piling injury upon insult; the loss of a prized magical treasure is bad enough!
(See also Table 88: Magical Items in the Dungeon Master Guide and Chapter 4: Magic Item Tables in the Tome of Magic)