The abandoned wall sand pit is located at the gamekeeper´s house Vlčinec, near the road from Horní Blatná to Nové Hamry. The sand pit on the eastern slope of Vlčí and Liščí hora was based on coarse-grained eluvia, i.e. weathered granite gravel. The mother rock is biotite granite with microscopic topaz, which belongs to the younger intrusive complex of the Karlovy Vary massif (type of Krušné hory).
The eluvium is 5-10m thick and consists of fine-grained feldspar and quartz gravel.
Large quartz tourmaline nodules are present in the gravelly weathered granite. Spherical bodies formed in the rock setting of residual boron-rich fluid, which itself bound iron from rock-forming biotite. Iron-rich tourmaline is called schorl and black radial aggregates called “tourmaline sun” are typical of it.
At the bottom of the sand pit there was a spontaneous development of wetland vegetation with rushes, club mosses, peat moss and other hydrophilic plants. Among them, the most famous Czech carnivorous plant, the round-leafed sun dew (Drosera rotundifolia) stands out above them all. It can be easily observed without a need to walk through deep peat bog. For this reason the habitat deserves strict protection.