Golden rocks obtained by training Woodcutting are part of the Statue of Rhiannon. Two are required each to complete the statue each time that it is built. Golden rocks may be stored inside a statue collection bag.
Cutting any wood, ivy, Jadinko Lair roots, overgrown idol jungle vines, or jungle near Tai Bwo Wannai as well as training at the sawmill.
Chopping logs or ivy in the Crwys Clan district in Prifddinas during the Voice of Seren will yield rocks the fastest.
It does not matter what is cut. There is a chance to get a rock every animation.