Found only in meteorites and the rarest of veins in magical areas, this ultra-hard metal adds to the quality of a weapon or suit of armour. Weapons fashioned from adamantine have a natural ability to bypass hardness when sundering weapons or attacking objects, ignoring hardness less than 20. Armour made from adamantine grants its wearer damage reduction of 1/— if it’s light armour, 2/— if it’s medium armour and 3/— if it’s heavy armour. Adamantine is so costly that weapons and armour made from it are always of masterwork quality; the masterwork cost is included in the prices given below. Thus, adamantine weapons and ammunition have a +1 enhancement bonus on attack rolls, and the armour check penalty of adamantine armour is lessened by 1 compared to ordinary armour of its type. Items without metal parts cannot be made from adamantine. An arrow could be made of adamantine, but a quarterstaff could not.
Only weapons, armour and shields normally made of metal can be fashioned from adamantine. Weapons, armour and shields normally made of steel that are made of adamantine have one-third more hit points than normal; for instance, an adamantine greatsword has 13 hit points instead of the normal 10 for steel.
Adamantine has 40 hit points per inch of thickness and hardness 20.
| Type of Adamantine Item | Item Cost Modifier |
|---|---|
| Ammunition | +60 gp |
| Shield | +2,000 gp |
| Light Armour | +5,000 gp |
| Medium Armour | +10,000 gp |
| Heavy Armour | +15,000 gp |
| Weapon | +3,000 gp |
Source: Dungeon Master’s Guide (Page 283)