The economic strength of Portuguese Brazil derived at first from sugar plantations in the north, established as early as the 1530s by one of the two successful donatários. But from the late 17th century onward, Brazil benefited at last from the mineral wealth which underpinned Spanish America. Gold was found in 1693 in the southern inland region of Minas Gerais. The discovery set off the first great gold rush of the Americas, opening up the interior as prospectors swarmed westwards, and underpinning Brazil's economy for much of the 18th century. Diamonds were also discovered in large quantities in the same region in the 18th century.