Puy Griou, Volcanic peak in Cantal, France

Puy Griou is a 1,690-metre summit on the ridge between the Cère and Jordanne valleys, half in Saint-Jacques-des-Blats and half in Mandailles. Its pointed peak rises on one side, with dark rock breaking through the snow, while a broad rounded ridge runs out to the right. A band of coniferous forest stands below the snowline.

Scientists once thought it was an eroded volcanic pipe, but geology revealed it actually formed as a phonolite dome around 6 million years ago. This finding reshaped understanding of how volcanoes developed in this part of France.

In Aurillac Occitan the summit is Puei Griu, from griea, "painful to climb"; north of the mountain, Auvergnat Occitan speakers call it Puei de Grion. The name describes the final 200 metres of ascent from the GR 400 ridge trail.

The climb starts from Super Lioran station using established hiking paths that require moderate fitness. Visit during warmer months when snow and ice do not block the routes.

Repeated freeze-thaw cycles during the Quaternary period shattered the volcanic rock into sharp-edged blocks, creating the scree slopes visible today. This physical weathering shaped the mountain's rough, fractured appearance.