The adamant plateskirt is the third best standard plateskirt, and the second best available to free players. It requires level 40 Defence to equip and can be produced via the Smithing skill at level 86, by using three adamant bars on an anvil. Doing so grants the player 187.5 Smithing experience. The adamant plateskirt is generally cheaper than adamant platelegs and has the exact same bonuses.
The adamant plateskirt (t) and adamant plateskirt (g) can be obtained through Level 2 Treasure Trails. They cannot be made through the Smithing skill. The adamant plateskirt (t) and (g) both have exact same bonuses as the regular untrimmed skirt, the other two skirts are mostly worn for show of wealth.