Diamonds of Nova Lorena Diamantina: The large stones in dispute in Colonial Brazil

Abstract

Brazil became the world's largest producer of diamonds in the 18th century with the discovery of alluvial diamonds in Minas Gerais, at the height of the Gold Cycle in the colonial period. Brazilian diamonds flooded the world market with countless stones of a few carats from the Jequitinhonha River valley, but large diamonds were also traded legally and illegally from the mid-18th century onwards, mainly with new discoveries in western Minas Gerais (Sertão do Abaeté), in the second extractive demarcation called Nova Lorena Diamantina. The Portuguese Crown assumed global leadership in the commercialization of diamonds produced in its main colony, where they controlled exploration with the Royal Diamond Extraction policy and the Diamantina Intendency established in the Tijuco village (Diamantina). However, much of the production was smuggled, especially stones larger than 20 carats that belonged by law to the Portuguese Crown. This is the story of two large diamonds from the Sertão do Abaeté that were found at the end of the 18th century, including a 138.5 carats stone that was the most famous Brazilian gem of this period and another of 35 carats, both belonging to the Portuguese Royal Treasury. The former is the Abaeté Diamond, discovered in 1792 by “sertanistas” in a tributary of that river, while the latter, whose origin was unknown, is shown by the present study to be a diamond found in 1799 in the Indaiá River by the famous prospector Isidoro, both coming from rivers of the Sertão do Abaeté.