The Feldstein near Lengfeld (the so-called "Hintere Feldstein" or "Teufelsstein auf dem Feldstein" is a natural geological monument) is part of a north-northeast-striking basalt vein that has been uncovered by earlier quarry work. It is one of the most important geotopes in Germany.

The basalt (alkali basalt) of the Hinterer Feldstein shows a columnar separation (five- and six-sided columns) and is a classic example of the pinnate or milestone position of the columns. The Hintere Feldstein has been protected as a natural geological monument since 1957.

The pinnacle or milestone formation of the basalt columns is very impressive for both laymen and experts. The outcrop is an instructive example of the separation of basalt columns in a passage.

The Feldstein is a popular excursion and hiking destination for the inhabitants of the region. According to the local chronicle of Lengfeld, the traditional Feldstein meeting has been held on Whit Monday since 1922, attracting a large number of visitors year after year.

Because of its regional fame, the Feldstein gave its name to our administrative community.