Quartz Mound

The Pfahl is a 150 km long quartz vein that runs through the Bavarian Forest in Germany. Geomorphologically, it represents a remnant ridge that was formed by weathering and erosion over millions of years.

The quartz mound is made up of quartz that was deposited as a hydrothermal vein about 275 million years ago within an existing fault structure. The quartz mound was probably active several times as a fault. Because the rock of the Quartz Mound was harder than the surrounding rocks, it was left standing as a wall when the softer rocks were carried away by erosion. Today, Quartz Mound forms a remnant ridge 150 kilometres long and 10 to 40 metres high. The bright white quartz of the mound consists of up to 98% silicic acid; any yellowish to reddish or grey colouration is caused by iron compounds and impurities.