Next day shipping on selected items!

Alluvial mining | What are alluvial diamonds?

on June 25, 2024

Alluvial diamonds are diamonds that have been removed over millions of years from their original or primary source, kimberlite, as a result of natural erosion and have been deposited in a new environment such as a riverbed, coastline or ocean floor. Today we will see what alluvial mining consists of and whether or not this process has ethical implications in the extraction of gemstones.

What is the alluvial mining?

Alluvial mining is the search for valuable minerals and geological material in sand or gravel deposits, which have been brought to these environments by the force of water or wind.

Traditionally, it is carried out on the banks of rivers and in coastal areas, taking advantage of the force of water to extract the precious minerals from the surface.

There are different techniques used such as sluicing, hydraulic mining and dredging.

Alluvial diamond mining at an industrial level requires a high investment and is governed by strict government regulations, so mining companies must be formalized and comply with all legal regulations.

Almost 10% of rough diamonds in the world market come from industrialized alluvial mining, and up to 14% is the result of informal or small-scale artisanal mining.


Alluvial mining history and evolution

Alluvial mining, the source of many precious gems and noble metals used in jewelry, has a rich history dating back to antiquity. Civilizations such as the Egyptians, Romans and Chinese already practiced this technique in an artisanal way to obtain gold and precious stones.

A turning point was the California Gold Rush of 1848, which not only popularized placer mining globally, but also spurred innovations such as the "long tom" and the "gold cradle," allowing more material to be processed and thus more jewelry to be obtained.

The 19th century brought significant advances. Edward Matteson's "hydraulic monitor" in 1853 revolutionized extraction, although its environmental impact led to restrictions. The introduction of large-scale dredges at the turn of the century transformed the industry, allowing access to gem-rich underwater deposits.

The 20th century saw a boom in demand for minerals, driven by events such as World War II. This led to the development of more sophisticated prospecting techniques, crucial to discovering new gemstone deposits.

The oil crisis in the 1970s and the rising price of gold renewed interest in placer mining. More efficient and mobile equipment was developed, facilitating the extraction of jewelry materials in remote locations.

In the modern era, technology has transformed the industry with GPS, advanced scanners and solar power. However, it is important to note that these innovations are not present in clandestine operations, which continue to use more rudimentary and potentially harmful methods. This applies to both diamond mining and gold alluvial deposits.

For jewelry lovers, understanding this history enriches the appreciation of each piece, recalling the long journey from riverbed to jewelry showcase.


What are alluvial deposits and where we find it?

Alluvial deposits are mainly found in the lower areas of rivers, forming deltas and plains, but they can also form at any other point where the riverbed overflows or stops its flow.

These deposits are essentially composed of clay, gravel, sand, silt and organic matter and are characterized by generating very fertile soils.

The alluvial diamond mining process consists of cleaning or filtering these sediments until the material to be commercialized is extracted.

The largest percentage of tin supply in the world is extracted from alluvial deposits, as well as gold, platinum and precious stones. They can be found on the Atlantic coast of South Africa and Namibia, in certain river waters of Angola, Ivory Coast, Guinea, Ghana, Sierra Leone, Democratic Republic of Congo, Central African Republic, Liberia, Tanzania, Togo, Venezuela, Guyana, South Africa and Brazil.

Rough alluvial diamonds were first discovered in South Africa.


The value of alluvial diamonds and gemstones

The marketing price is closely related to the process of mining alluvial diamonds. In the case of informal mining, where there is no foreign capital participation, production is sold directly to local or international markets by smuggling, at a lower cost than in formal mining.

There is no payment of taxes or compliance with regulations, so the final price of the product is affected.

Informal mining production costs are considerably lower than industrialized mining, which means that the supply of diamonds and gems is relatively stable and does not experience large price fluctuations.

This supposed price stability may vary if the diamond enters the smuggling chain, where prices vary thanks to the spiral of corruption.

At Albert Hern, we make every effort to validate that none of our materials come from exploitative or fraudulent sources, be it placer mining or otherwise.


Ethical implications

It is estimated that illegal mining accounts for approximately 20% of total gold and diamond production of the world's traded gemstones.

Informal alluvial mining not only has harmful consequences for the environment, but is also an activity that often violates the rights of miners with forced and precarious working conditions.

In diamond mining areas in Africa, for example, miners can be paid less than $1 a day and illiteracy and mortality rates can be quite high. The struggle for land rights is also a major ethical conflict surrounding mining, with local communities often being disadvantaged by governments or large industries that make use of geographical areas for mining.

During the process of extracting placer diamonds, as the product of alluvial mining is also known, many sediments and particles are released that silt up river water and contribute to turbidity.

Historically, illegal mining has been linked to the financing of armed conflicts in different regions of the world and gave rise to the concept of blood diamonds. Respected and formal jewelry houses do not work with diamonds from this type of mining.

For example, at Albert Hern you can find a wide variety of ethically sourced diamond jewelry, such as:


Alluvial diamond mining curiosities 

Although this is a mining strategy that has been clouded by conflicts, the reality is that it can be put to effective use if done responsibly and with strict legal controls. This same, for example, has been the subject of many curiosities over time, such as, for example:

  • In the year 2022 was found in the alluvial diamond mine of Lulo, in Angola, the probably largest pink diamond in the last 300 years. Named Lulo Rose, these 170 carat stone has attracted worldwide attention. 
  • Only 1 in 10 thousand diamonds that are mined have color, and only 1 in 100 exceed the size of 10.8 carats. 
  • Alluvial mining of diamonds is similar to that of gold, and in both forms, washing and screening of the precious minerals are used. Angola's mines are among the top 10 diamond producers in the world market. 
  • The oldest and most traditional way of extracting diamonds is through alluvial mining, which originated centuries ago in India and has spread throughout the different continents, mainly in Africa and in Latin America, in the Brazilian Amazon.
  • In the sedimentary alluvial deposits are found rubies and alluvial diamonds that are highly valued for their beauty and particular color. The Rosser Reeves Ruby, for example, is the largest ruby found and weighs 138.7. It was found in Sri Lanka in 1965.

Thank you for joining us on this journey through alluvial mining and its complex ethical implications. We reiterate our effort at Albert Hern to work exclusively with precious and semi-precious stones and metals of high quality, free of conflict, blood and exploitation, which we faithfully believe are more brilliant and beautiful, fulfilling their role as symbolic jewelry, inheritable and loaded with deep meaning.



  • What does alluvial mining mean?

    Alluvial mining is a method of extracting minerals and gemstones, especially gold and diamonds, by digging up alluvial deposits. These deposits are sediments that have been washed and deposited by water in rivers, streams, or on coastlines. It's a mining practice that's been around for thousands of years and is still common today.

  • What do alluvial diamonds look like?

    Alluvial diamonds are those found in alluvial deposits. Often, these diamonds have been unearthed and transported by water, which can result in wear and a rounded shape. They can vary in size and clarity but are generally lower quality compared to diamonds from traditional mines.

  • How do you find alluvial diamonds?

    Alluvial diamonds are discovered by digging up and washing sediments in areas known to have alluvial deposits. This might involve using simple equipment like shovels and sieves or more mechanized methods. Artisanal miners often work in rivers and streams, where water has eroded the terrain and exposed diamonds.

  • What is the meaning of alluvial in simple words?

    Alluvial describes sediments that have been deposited by flowing water. It comes from the word "alluvium," meaning flood or water flow. Simply put, it refers to the mud, sand, and gravel left behind by rivers or floods.


Please note, comments must be approved before they are published


Net Orders Checkout

Item Price Qty Total
Subtotal $0.00

Shipping Address

Shipping Methods