They can be crafted at the Cosmic altar in Zanaris through the Runecrafting skill at level 27 for 8 experience per pure essence after the Lost City quest. They can also be purchased at the Mage Arena bank in the Wilderness. At level 59 Runecrafting, the amount crafted doubles to two cosmic runes per pure essence. There is a cosmic rune spawn in the northwestern part of Wilderness, on the icy area just south of the members' gate. A total of three cosmic runes spawn here. This is a dangerous area due to player killers and aggressive ice warriors and ice giants.