Strange rocks obtained by training Runecrafting are part of the Dahmaroc statue. Two Strange rocks from each skill are required to complete the statue, which can be built once per week. Strange rocks may be stored inside a statue collection bag.
Crafting runes, also during the Great Orb Project minigame and the Runespan. The Wicked hood is helpful when going after these rocks. Bring along all owned runecrafting pouches as well. Generally, using the wicked hood method daily gives a high chance for at least one rock, particularly if the player has the hood fully upgraded.