Description

#3031 – A 4.3 x 1.06 x 1.02 – inch terminated Smoky Quartz crystal from Rio Grande Do Sul, Brazil.  Smoky quartz from Rio Grande do Sul, Brazil, generally forms from hydrothermal fluids within the cavities (vugs/geodes) of basaltic volcanic rocks. The characteristic smoky color is a result of natural gamma radiation from trace radioactive elements in the surrounding host rock acting on the quartz crystals, which contain minor aluminum impurities.