|Release||12 April 2010 (Update)|
|Max output||5 (10 with gathering ring)|
|Full of valuable resources. (Tier 10)|
Promethium rock is a mining rock used in the Dungeoneering skill, requiring 90 Mining to mine and will always contain 5 ores. However, the player can crush up to 4 out of 5 of these ores whilst extracting them from the rock. This means that each rock can give between 1-5 Promethium ores before it is depleted and unlike rocks on Gielinor it would not respawn. With a gatherer ring, it is possible to mine up to 10 ores.
The player is given a message when they have successfully mined an ore or if they have crushed it; however, these messages can be hidden by the game filter. It is a Tier 10 rock and provides the highest quality ore that can be mined in the Dungeoneering skill. A Complexity level of 3 or higher is required to find this rock whilst Dungeoneering.