The nunatak is about high above sea level. Most of the mountain is buried beneath the Viedma Glacier of the Southern Patagonian Ice Field and only parts of it crop out. The outcropping nunatak is elongated in north-south direction. A number of structures interpreted as craters and concave depressions are found especially on the southern part of the volcano, some of which are lined up in north-south direction. The northern sector of the volcano was apparently more heavily affected by glacial erosion; conversely, several craters in the southern sector appear to be young. The nunatak shows clear evidence of glacial action, including glacial striations and coverage by glacial drifts; the Viedma glacier may once have crossed the nunatak in its central part. Rock samples taken from the nunatak are Jurassic metamorphic rocks, including gneiss and schists, and no evidence of magmatic rocks was found in a 1958-1959 expedition.