The Gallow Hill, which was cut through with the building of A 62 in the middle of the 1970ies by enormous earth movements, is the place of origin, if the the agate collector is talking of “Autobahn-Agates”. Apart from many further important excavations (e.g. Leitzweiler bridge) it was straight this place, which supplied a multiplicity of first-class and typically formed agates. The place of discovery is also under the name "Freisener cross" well-known, there after conclusion of the work on this hill a five meters high, iron cross plastics was established. The amount of findings was likewise enormous on good days. Nowadays one must ask oneself for the remaining of all these nodules, which gathered the collectors like crows behind the plow from the enormous gutters, which broke the at present largest dozers with their rock-teeth. Nowadays these agates are rarieties.
Distinctive characteristics of Gallow-Hill agates are:
- their form: The nodules resemble smaller versions of torpedoes, i.e. they often are in the cross section circle-shaped - in the longitudinal extending they correspond to long-drawn-out drops.
- their fine banding, which is strongly rejected often by irregular pressure drop during maturing the silicate gel. A multiplicity of extension tubes is likewise typical therefore.
- pseudomorhs after early, often concentrically formed carbonate aggregates, which can be identifiable by the edge of the nodule.
- their colouring. Gallow-Hill agates are porcellain-agates, which do not appear any more transparency, but transluzid to opak. The basic colour of the pattern is often white. On this background then several pastels are showing up in the tender contrast. Apart from usual tones like pink, brownish or yellowish also green occurs.
- the enriching of the pattern by secondarily pigmention after the formation of the agate. The supply of ferric oxides effects linelike or spotted patterns. Sometimes the patterns are showing the “Liesegang-Phenomenon” too.