Diamonds were not the first precious materials mined in Brazil. An earlier gold rush occurred – one of the first in the West after colonisation – and gold remains an important mining concern in Brazil. Despite this, Brazil was the first country in the West to produce diamonds via the washing of alluvial deposits. This first occurred in the 1700s.
For the next century, Brazil was the world’s leader in producing diamonds of high quality. It still ranks highly, but lost this particular title after a new field was discovered near Kimberly, South Africa.
Brazil is also home to a number of major river systems. Nearly all of them contain alluvial diamonds. This means that Brazil produces a vast array of diamonds and produces many of them through the discovery of placer deposits.
A placer deposit is formed when valuable minerals accumulate via gravity separation in bands of sediment. As the sediment is eroded and revealed, these placers are also revealed. The gravity separation occurs when materials are denser and resistant to erosion themselves. This means that these materials will settle in specific sedimentary areas. They are often revealed when the sediments are worn away faster than the hardier placers can be.
An alluvial placer deposit, the kind often discovered in Brazil, occurs near rivers and streams, particularly near bends and changes in slope. These are areas where water acts to wear away sand and gravel, leaving harder deposits like diamonds, gold, and other gemstones behind.
Compared to more classical open pit mining, this means that diamond operations may be greater in number but smaller in size than is seen in most countries. This is necessary when these operations must be a little more nomadic and exploratory in nature. This isn’t to say Brazil doesn’t house larger operations as well; simply that it features many smaller-scale operations at the same time.
Difficulties and Concerns
One of the difficulties comes in ensuring all these operations are environmentally safe. Brazil is rich in natural resources, and thus home to a number of mining concerns. Bauxite, chromite, coal, cobalt, copper, gold, iron ore, lead, manganese, nickel, platinum, thorium, tin, uranium, and zinc are also all mined in quantity in Brazil. More rare earth elements such as niobium and tantalum are also mined here. This means that Brazil has long struggled with balancing mining its rich natural resources against the delicate ecology that must be balanced there.
Another difficulty rests in regulating diamond mining so that it doesn’t put Brazil’s indigenous communities at risk. When diamonds are (comparatively) easy to find along the side of a river, it’s more difficult to regulate who’s taking them and how careful they’re being. It is one of the larger challenges Brazil faces and it’s a good reason why it’s best to buy diamonds from larger, vetted sources.
Neither is Brazil the only South American country with a considerable diamond reserve profile. Guyana, Uruguay, and Venezuela also contain rich reserves with different levels of mining. Brazil offers a fascinating profile for a country that’s been mining diamonds for longer than almost any other.