Jánské kameny, Mountain summit in Saxony, Germany

Jánské kameny is a 604 m summit in the Lusatian Mountains whose top is formed by a curved basalt dyke up to 5 m thick and 15 m high, running east-west along the German-Czech border. The ridge consists of nepheline tephrite with horizontal columns and is protected as a geological natural monument.

Since the 1635 cession of Upper Lusatia, the border between Saxony and Bohemia has run across the Johannisstein, whose summit belongs to Bohemia. In 1880 a guesthouse was built on the Bohemian side, followed a year later by a viewing platform; it was enlarged in 1927 into a mountain hotel with a dance hall. After 1945 the complex stood unused, served from 1959 to 1968 as a GDR youth hostel, and was gradually restored from 2001.

The name Jánské kameny (Johannisstein) refers to St John, and the yellow-marked trail from Krompach to the Oybin border crossing passes the rocks. Since 2006 a nature trail under one kilometre long branches off it, with four information boards explaining the basalt wall and the site.

The site is reached via a roughly one-kilometre educational trail branching off the yellow-marked route from Krompach to Saxony through the Krompach/Oybin border crossing. The trail, built in 2006, has four information boards on Jánské kameny. The rock wall itself lies between 587 and 604 m above sea level.

The summit ridge is a basalt dyke up to five metres thick and fifteen metres high, bending east to west along the border; its horizontal nepheline tephrite columns are protected as a geological natural monument, and the base is Upper Turonian sandstone.