A larger rock is used in the Tears of Guthix Distraction and Diversion.
It may be mined from the Magic stone mine across the chasm by Tears of Guthix, provided the player has both 80 Mining and 80 Crafting and has spoken to Juna about making a more ornate bowl. Any of the rocks in the mine can be used.
The larger rock may be crafted into an Ornate bowl, which can be taken to Juna to gain extra experience in Tears of Guthix.