On the mineral days 2014 in Munich I could discover agates from the Inner Mongolia at the booth of a Chinese trader who offered many different arts and crafts, and by the way some minerals in boxes. He cited the Tengger Desert in Alxa Zuquoi, Nei Menggu as the location.
According to the information of the dealer agates in the Tengger Desert in certain areas are scattered on the surface. Wheathered out from the bedrock exposed here to the sun and the wind in the desert. Thereby, typical carnelian colors arise in brownish-red, yellow and orange, on the other hand they get their peculiar shape. Whole nodules or fragments are cut by the wind and rounded. This shape is called in german "Windkanter". They remember sometimes specific models, such as this "seal". These forms were also the reason why the agates were picked up.
A large part of the occurring nodules consist of a cloudlike chalcedony, which can be slightly bluish or pink in colour. Also multi-coloured complex structured chalcedony occurs. Soft banded agates seem rare. In addition to this "fortification-agates” also gravitational secluded agate bands, so-called "waterlevel agate" can be found.
In the inside of the nodules it comes also to the formation of pseudomorphs ("Sagenitic agate"). The formation of a bottom-level originally formed parallel striped and then ragged (15) is interesting.