Mongolian agates are surface findings out of the northwestern and central Gobi desert. Very well known ( and highly searched for ) are the agates from Burugdi mountain in nortwestern Gobi. At this place yellowish and blue chalcedony-nodules - very often with a botryoidal cavity in the center - can be found. Another typical phenomenon are mossy-like structures as inclusions in the nodules. It is possible to find chalcedony-nodules sitting on early formed carbonate-aggregates. Sometimes nodules with a nice black and white contrast can be found. Items with a fine-lined fortification banding are rare.