Brazil was the world's leading source of diamonds for about 150 years, from the 1720s until the South African discoveries of the 1860s and 1870s. The stones came from river gravels in the highlands of Minas Gerais, around the town now called Diamantina. The Portuguese crown tried to control every carat through a strict royal monopoly, while independent miners known as garimpeiros worked the rivers in its shadow. Their story runs through Brazilian history and through the history of the world diamond trade.
Discovery in Minas Gerais
In the late 17th and early 18th centuries, gold rushes drew settlers into the interior of Minas Gerais. Miners panning for gold in the streams of the Serra do Espinhaço found small, bright crystals in their pans. According to tradition they used them as counters in card games before anyone identified them as diamonds.
The find was reported to the Portuguese authorities around 1729, and the governor of Minas Gerais announced it officially that year. The center of the new diggings was the settlement of Arraial do Tijuco, which later became the town of Diamantina. Diamonds also turned up in other parts of Minas Gerais and, later, in Bahia, Mato Grosso and Goiás.
For context on the wider gem wealth of the state, including its topaz, tourmaline and aquamarine, see the page on gems of Minas Gerais.
The Diamond District and the royal monopoly
Portugal treated the diamonds as crown property. In the 1730s the authorities marked out a Diamond District (Distrito Diamantino) around Tijuco and placed it under tight control. Entry and exit were restricted, and outsiders needed permission to travel there.
The crown first taxed miners by the number of enslaved workers they used, then shifted to a contract system. From 1739 to 1771 the right to mine was leased to private contractors, who paid the crown for the privilege. The best known was João Fernandes de Oliveira, whose relationship with Chica da Silva, a formerly enslaved woman who became one of the wealthiest people in Tijuco, has become part of Brazilian folklore and popular culture.
In 1771 the Marquis of Pombal ended the contracts and created the Real Extração, a royal administration that ran the mines directly for the crown. This regime lasted into the 19th century. Officials controlled the labor force, sealed the diamonds in boxes and shipped them to Lisbon.
Who did the work
Most of the digging was done by enslaved Africans and their descendants. They worked in the rivers diverting channels, shoveling gravel and washing it in wooden troughs while overseers watched for theft. Accounts from the period describe harsh conditions and punishments for concealing stones. Enslaved workers who found an exceptionally large diamond could sometimes receive their freedom as a reward, according to contemporary reports.
The work followed the logic of all alluvial mining: find the gravel layers where heavy minerals concentrate, then wash away the lighter material. The methods are compared with modern techniques on the page about how diamonds are mined.
Garimpeiros
Alongside the official operations, independent prospectors called garimpeiros mined illegally. The word is usually traced to "grimpa," a term for the high ground where they hid from royal patrols. Garimpeiros risked heavy penalties, and smuggling was constant. Historians believe a large share of Brazil's production left the country unrecorded.
After Brazil became independent in 1822 and the royal monopoly faded, small-scale mining by garimpeiros became the normal way to produce diamonds in Brazil. Garimpeiros spread to new fields in Bahia's Chapada Diamantina in the 1840s and later into Mato Grosso and other states. They worked with shovels, sieves and later with pumps and small dredges. Garimpo mining has continued into modern times, and it has often raised conflicts over land rights, river damage and mercury use where gold and diamonds occur together.
Brazilian diamonds and the world market
When Brazilian stones reached Europe in quantity, the diamond trade changed. India's Golconda region had been the main source for centuries (see the Golconda diamond mines), and some European merchants at first doubted that Brazilian diamonds were genuine. A story often repeated holds that traders shipped Brazilian rough to India so it could be resold in Europe as Indian. The large increase in supply pushed prices down in the 1730s, and Portugal limited output to protect them.
Lisbon became a diamond center, and most rough passed on to Amsterdam and London for cutting and sale. The cutting industries in those cities grew on this supply; the page on the history of diamond cutting traces how cuts changed during the 18th century. Brazil's dominance ended after diamonds were found in South Africa in 1867 and huge kimberlite deposits opened at Kimberley, covered on the page on diamond mines of South Africa.
Famous Brazilian diamonds
Brazil produced some large stones that became well known:
- The Estrela do Sul (Star of the South), about 261 carats as rough, found by an enslaved woman in Minas Gerais in 1853. It was cut into a cushion of about 128 carats.
- The Presidente Vargas, about 727 carats as rough, found in 1938 in the Santo Antônio River near Coromandel, Minas Gerais and later cut into many smaller stones.
- The Darcy Vargas, a brown stone of about 455 carats found in 1939 in the same region.
Brazil also produced colored diamonds, and stones from the Diamantina region were prized for clarity and good crystal shapes. The page on diamond geology explains why rivers tend to concentrate the best crystals.
Where the diamonds came from
For a long time geologists could not find the source rocks of Brazil's diamonds. Much of the Diamantina material appears to have been recycled through ancient sedimentary rocks, such as conglomerates, before ending up in modern rivers. Kimberlites have since been found in several states, and some have been tested for mining, but Brazil has never developed a kimberlite industry on the scale of Africa, Russia or Canada.
Frequently asked questions
When were diamonds discovered in Brazil?
Gold miners in Minas Gerais found diamonds in the 1720s, and the find was announced officially around 1729. Brazil then became the world's main source until the 1870s.
What is a garimpeiro?
A garimpeiro is an independent, small-scale miner in Brazil. The term began with illegal miners who hid from royal patrols during the colonial monopoly.
What is Diamantina?
Diamantina is the town in Minas Gerais that grew from the diamond camp of Arraial do Tijuco. It was the center of the colonial Diamond District, and its historic center is a UNESCO World Heritage Site.
Why did Brazil stop being the top diamond producer?
Its river gravels became less productive, and the discovery of rich kimberlite deposits in South Africa after 1867 shifted the world's supply.