The adamant plateskirt is the third best standard plateskirt, and the second best available to free players. It requires level 40 Defence to equip. 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 the exact same bonuses as the regular untrimmed skirt and are mostly worn for show of wealth.