A first-class location for very fine agate specimens is Ploczki Gorne in Lower Silesia. These nodular agates are desirable collectors-items if they are showing an intensively bluish-purple colour. A lot of other fine colours do occur here too - red, yellow and brownish tones.
One typical structure for this location are radial agregated quarzcrystals enclosed in chalcedony.
Some pattern are giving a three-dimensional illusion, because an opaque centre is embedded in clear chalcedony.
Only in a few cases agate-nodules from Ploczki Gorne are reaching sizes bigger than 4 inches.