Rio Grande do Sul, South Region, Brazil

Rio Grande to Sul is best known to collectors, mineralogists and museum curators for the wonderful specimens of agate and amethyst that come from the amygdaloidal cavities in the huge basalt formation know as the Parana basalts. The mining of amethyst crystals are currently centered mostly around the little town of Ametista do Sul although much amethyst and agate is and has been mined from localities up to and further than 100 km away. Each year two to four thousand tons of agate and amethyst is exported from this region to all parts of the world. In most cases it is not possible to look at a cluster of amethyst crystals or a particular agate slab and know with certainty which of these localities it came from because they often produce similar material. However, some amethyst and agate specimens are distinctive enough that it is possible to place them as being from a particular area like the Umbu agates from the area around Salto do Jaquai or the amethyst "flowers" and calcite crystal specimen from the area around Frederico Westphalen. Rock Currier (2009)

References:
- Balzer, R. (2003): Rio Grande do Sul, Brasilien - Landschaften - Menschen - edle Steine. Wenzel Verlag, Marburg, 235 pp. (in German)