Two Kilometers north of the Iburg Castle is an agate finding-location in the middle of the forest that was uncovered by the storm Lothar in the year 1999. The place is called “Pfeiffers Felsen” (Pfeiffers rock). Here collectors could find a lot of lithophysae with chacteristical reddish coloured agate inside. Very often pseudomorphs after tabular or platy minerals are formed.