In tertiary aged gravel, deposited by a so called “prehistoric River Mosel” 29 million years ago, were thes agates and quartz-varieties collected.
These gravel-deposits are situated around the township of Arenrath in the Eifel. The origin of these agates is not known exactly - one possibility for their origin are the agate-bearing vulcanic-rocks around Leitzweiler ( a presentation about this thesis is given here).
In these gravel a lot of different pebbles do occur:fortification-agates, mossy agates, jaspers, “water-level-”-banded agates, pseudomorphic formations, silicated devonian-aged shale with agatized fossils, stromatolithic algae and petrified wood.
During transportation and erosion the shape of the stones changed by edge smoothening. The originally colour was lost - but the contrasting in the banding was enforced. The phanerocrystalinic formation in the center of the nodules became more transparent.