Marmorstein, Rock formation in Hochtaunuskreis, Germany.

Marmorstein is a group of Taunus quartzite rocks on the Taunus main ridge between Herzberg and Saalburgpass, at 444 to 460 m above sea level above the König-Wilhelms-Weg. The quartzite's marbled colour gives the formation its name.

The formation developed over millions of years through geological processes that left quartzite layers throughout the Taunus region. This rock composition continues to shape the local landscape today.

The name refers to the marbled colouring of the Taunus quartzite, as described by Hermin Herr. Since the 19th century the rocks have been a popular excursion destination, often combined with a climb of the Herzbergturm and a visit to the Saalburg. The Nymphenquelle on the Emesberg and the Jupitersäule stand nearby.

The site is accessible via marked hiking trails and has resting spots along the routes. Visitors should wear sturdy footwear since the terrain is uneven and sometimes steep.

Despite its name suggesting marble, the formation is composed of Taunus quartzite, the area's characteristic stone. This material is much harder and older than actual marble.