Mont Gerbier de Jonc

Mont Gerbier de Jonc is a volcanic mountain peak in Ardèche featuring distinctive columnar phonolite rock formations that rise steeply from the surrounding landscape. The summit reaches about 1,551 meters (5,089 feet) and displays geometric hexagonal patterns across its stone faces created by the cooling of ancient lava.

The mountain formed through volcanic activity approximately 8 million years ago when thick lava created a dome within an ancient volcano's crater. Over time, erosion wore away the surrounding landscape, leaving this harder phonolite rock standing as a prominent landmark in the region.

Three springs emerge at the base of the mountain marking the source of the Loire River, a waterway deeply rooted in French identity and regional life. This spot has long held symbolic meaning as the birthplace of one of the country's most important rivers.

The mountain is accessible via marked trails of varying difficulty, with the main route taking around 90 minutes to reach the summit. Visitors should expect changeable weather at altitude and wear sturdy footwear since paths are rocky and can be steep in places.

As the ancient lava cooled, it naturally formed hexagonal columnar patterns in the phonolite rock, creating geometric shapes that look almost sculpted by hand. This cooling process produces vertical joints that fracture the stone into neat, architectural-like columns rarely seen elsewhere.

Location: Ardèche

Elevation above the sea: 1,551 m

Made from material: phonolite

Address: Mont Gerbier de Jonc, 07310 Saint-Martial, France

GPS coordinates: 44.84388,4.21986

Latest update: January 25, 2026 18:56