There's a rock revolution taking over thousands of Victorian parks and playgrounds, but it has nothing to do with loud music.

Sure there are stones, but instead of rolling they're being picked up, painted and put back down, ready for one of more than 30,000 people to find them. All because of a Facebook group called "Vic Rocks".

Lotte Chick and Abbey Guengerich rock hunting in Bentleigh. Credit:Justin McManus

Popular with children, parents and the elderly alike, Vic Rocks participants collect rocks, paint them and then place them in parks for others to hunt down.

Some who find the rocks are part of the 30,000 strong Facebook group, but others aren't; they just happen to stumble across the colourful stones while out and about. To help explain the spontaneous find, each rock directs people to the online community, and many members have been recruited this way.