Material is a basic property of an item in ADOM. An item can only be made of one material, even if by logic it should have parts consisting of other materials as well (although the game acknowledges this through weight differences).
The material of an item has several implications:
- Damage resistance: items in ADOM can be damaged/destroyed by a variety of sources. Item base material defines which damage sources affect it and how high is the chance to resist an applicable source (although there are several other factors in damage resist rolls). Additional properties of the item may override or improve innate damage resistance (e.g. items granting intrinsic elemental resistance/immunity are also immune to the corresponding element regardless of their base material; artifact items cannot be destroyed).
- Weight: As in the real world, different materials in ADOM have different density and thus influence the effective weight of items. There are no strict rules for weight calculation — unique items and different item groups have practically arbitrary weights — however, within a single item group (e.g. a spear, coming in 5 different variations, made out of stone, iron, mithril, adamantium, and eternium) a certain pattern is preserved.
The following table provides a summary of the above two properties applied to materials present in ADOM. Weight modifiers are given in relation to the weight of iron, and damage source reference uses the following notation:
- - — material is immune to source,
- + — material is susceptible to source,
- ++ — material is highly susceptible to source,
|Iron||1x||+||-||-||+||++||++||+||+||Can be smithed, damages Mist Elves in direct contact (item equipped), affected by rust monsters|
|Mithril||0.8x||-||-||-||+||+||-||+||+||Can be smithed|
|Adamantium||0.7x||-||-||-||+||+||-||+||-||Can be smithed|
|Eternium||0.5x||-||-||-||-||-||-||-||-||Can be smithed|
|Glass||N/A||+||+||+||-||-||-||++||+||Shatters when thrown or kicked|
- Main article: Material-based identification
Various items are made of the same material in every game. Thus, all items of a certain type (e.g. rings, amulets) form several groups differentiated by material. Remembering item-material groups can allow the player to minimize the risks of using unidentified items during the game. Additional item features (unique weight values, rarity considerations) can be used by the player to further improve meta-identification process.