In the year 2007 I could buy from my good friend Christian Weinz agates from recent findings in Salto. This type was arranged in Brazil under the edition to receive as much as possible stones with geodes. Customers should cut those specimen themself.
Many of these nodules with very bright surface contained then also cavities, which were occupied with amethyste or crystallized (“druzy”) quartz. “Water-level-banding” was quite common with these pieces, just like similarly formed, whitish layered opal.
Very interesting were specimen which exhibited plumes, once as white hanging stalactitical formations and twice as awesome vellow-brown tree-like aggregates.