Volcanic ash and twin globes: Montblanc's 1858 Geosphere Mount Elbrouz

Montblanc's 1858 Geosphere 0 Oxygen Mount Elbrouz is one of the most material-led exploration watches of 2026. Its 43.5mm case combines titanium with an unusual composite containing volcanic ash, aluminised basalt fibres, calcium carbonate and plant-derived resin. A glowing outline of Mount Elbrouz runs along the case flank, while the caseback carries a colour-engraved rendering of the mountain's twin summits.

On the dial, two rotating globes depict the Northern and Southern Hemispheres, surrounded by day/night rings. A subdial at nine handles another time zone, while the date remains at three. Automatic Calibre MB 29.25 powers the world-time mechanism, with around 42 hours in reserve. Instead of illustrating altitude using yet another mountain logo, Montblanc puts the geology of the actual mountain into the watch's architecture.

The edition of 829 pieces references 1829, the year of the first recorded climb of Elbrouz's higher summit. Two interchangeable rubber straps, ivory and light brown, complete an object that is as much landscape study as horological instrument.