The oldest known rock main content.

The oldest known rock

Part of Hall of Planet Earth.

The Oldest Known Rock_HERO

Exhibition Text

By dating the zircons embedded within the Acasta gneiss, geologists have determined its age to be 3.96 billion years. This rock’s composition establishes it as part of a continent, indicating that continents existed nearly four billion years ago.

Donated by Royal Ontario Museum, Toronto, Canada

For Educators