Its summit consists of pyroclastic rocks (Schweißschlacken) that form a volcanic crater that is open towards the east.

This is where the basalt masses flowed out, forming a semicircle on the eastern slope of the mountain.

Cut langlauf tracks, a toboggan slope and ski hire hut are available.

[1] On 20 September 1978, the Ernstberg was designated by the district council at Trier as a nature reserve.

[citation needed] Its conservation aim is the preservation of the Early Pleistocene stratovolcano with its distinctive ring-shaped arrangement of its pyroclastic rock and basalt layers (Einlagerungen) (nepheline-leutzitite).