Complex sentence: In the 1720s the rush suffered another stimulus with the discovery of diamonds and the two mining industries grew fast and by the 18th Century perhaps 80 percent of the gold in Europe originated in Brazil.
Split into simpler sentences: In the 1720s, the rush suffered another stimulus with the discovery of diamonds and the two mining industries grew fast. By the 18th century, perhaps 80 percent of the gold in Europe originated in Brazil.