Runite ore

Runite ore can be found in the Dwarven mines and at the Fremennik islands. It requires level 85 Mining to be mined, and grant 892 experience per ore.

Runite ore can be smelted into an Rune bar using a Furnace, using 1 Runite ore and 4 Coal ores. You can also use the spell Superheat on a Runite ore to get an Rune bar, but you still need to have atleast 4 Coal ores, 4 fire runes and 1 nature rune in your inventory to use spell. Using this spell will grant 200 Smithing experience and 692 Magic experience. Rune bars are further refined in the Smithing skill, granting 560 Smithing experience per bar used when smelt into other items.