Diamantino is a municipality in Mato Grosso state in Brazil. It has a population of 18.580, and is near Diamantino River. It is 1837 feet above sea-level, and sits at the foot of the Mato Grosso plateau. Its history dates from 1730 as a gold mining settlement. In 1746, diamonds were discovered, which made the town's population swell and prosper. The amount of diamonds was greatly overestimated, and the town population has gone into steady decline ever since.