Adamantite rocks are a type of scenery which give adamantite ore when mined. Level 70 in the mining skill is required to mine adamantite rocks. Doing so gives 95 experience when mined successfully.
A depleted rock takes between 180 and 220 seconds to respawn, depending on the population of the server.
They are not commonly mined due to the low number of them in the game; the slow rate of re spawn, the high requirement to mine them, and the products resulting from smiting being inferior to those made from runite.