Rubium veins are the source of a rare ore, rubium, that players can only mine deep within the Witchaven Dungeon during and after the Kennith's Concerns quest.
Rubium has high reactivity with water, thus during the quest, it is used on the steamers to raise the room temperature significantly in order to disrupt the workers. However the rubium will burn up if you get kicked out, so you still need to be careful not to get caught. After the quest, players may sell rubium to Ezekial Lovecraft in his fishing shop, based in Witchaven for 10 coins per ore. Selling this will also update your Ardougne Tasks. Players may also mix it into a guam potion (unf) at 31 Herblore to make a Super Fishing Explosive. Super Fishing Explosives give 55 xp to make and will generate 150 damage to Mogres whilst luring.
In total, there are only twelve rubium veins located in the mine, requiring 46 Mining to be mined and yielding 17.5 experience points for each successful dig.
Rubium will respawn when a player leaves and reenters the mine room.