Moeraki Boulders

Dotted along a stretch of Koekohe Beach on the Otago coast of New Zealand, the Moeraki Boulders are a collection of unusually large, spherical stone formations that rest on the sand like scattered marbles. These boulders are septarian concretions, formed over millions of years through the gradual accumulation of minerals and sediment around a hard core. Over millennia, coastal erosion has slowly worn away the surrounding mudstone cliffs, leaving the heavy stone spheres exposed on the shore as the tide recedes.

Most of the boulders measure between one and two meters in diameter, with some weighing several tonnes. Their surfaces are often etched with intricate, branching patterns of cracks filled with calcite, which formed as the wet sediment shrank and hardened inside the earth long before they saw the light of day. While similar concretions exist in other parts of the world, few locations display them in such concentration, scale, and dramatic coastal setting.

Visitors walking down from the nearby parking area and cafe encounter a landscape that feels strangely ancient and sculptural. Depending on the tide, the boulders are either partially submerged in the surf or resting entirely on the damp sand, offering endless angles for photography and quiet contemplation of geological time. The interplay of crashing waves against these smooth, weathered spheres creates a stark contrast between the fluid power of the ocean and the enduring density of stone.