Overview - Tanzania Diamonds Industry and Williamson Diamond Mine

Overview: Tanzania Diamonds Industry and Williamson Diamond Mine

Diamonds from Tanzania are highly valued for their exceptional quality, and the country’s diamond reserves are estimated to be one of the richest in the world. 

In this article, we’ll explore everything about diamond mining in Tanzania. From the Tanzania diamond mines, to the types of diamonds, how to purchase them, and Tanzania breaking news about diamonds!

Where are Diamonds Found in Tanzania?

The primary site for diamond extraction in Tanzania is the Williamson diamond mine, situated to the south of the town of Mwanza in the northeast region of the country.

Williamson Diamond Mining Company

The Williamson Diamond Quarry [a. k. a the Mwadui quarry] is a diamond quarry in Tanzania, located 23 kilometers [14 miles] northeast of the district of Shinyanga. It is often viewed as the world’s first large diamond quarry after South Africa. Dr. John Thoburn W., a geologist from Canada, founded the mine in 1940, and it has been in operation to date, giving it the status of one of the world’s longest continually working diamond mines. It has produced about 19 million stones [3,800 kilograms] of Tanzania diamonds throughout its lifespan. The Guardian reported in 2020 that a high-grade pink gem from the mine might be worth up to $700,000 per carat.

The Williamson quarry was previously held by Dr. Williamson, the mine’s namesake, but was eventually nationalized by the Tanzanian government. Petra Diamonds Tanzania has held 75 percent of the mine since February 2009, with the Tanzanian government controlling the remaining 25 percent. The mine was investigated in 2020 for potential human rights alleged violations.


The Williamson mining company is a big open pit quarry with a depth of approximately 90 meters [300 feet]. The Williamson mining company features four distinct operations: gravel mining, pit mining, and tailings re-treatment to recover lost Tanzania diamonds, both on and next to the site where gravel has been alluvially placed. The biggest of the four businesses is open-pit mining as well as tailings re-treatment. The mine employs roughly 1,100 people, the majority of whom are Tanzanians.


The main diamond mining areas in Tanzania is the Williamson Diamond Mine (also known as the Mwadui mine).

This mine lies about 160 km [99 miles] south of Mwanza, in Shinyanga Region’s Kishapu District. The site was named “Mwadui” after a village chief by Dr. Williamson, the site’s first owner, discoverer, and mine’s namesake; “Mwadui” and Williamson” are now almost identical in the diamond extraction industry.

You can find the Williamson diamond mine Tanzania contact details and the mwadui diamond mine tanzania contacts here! 


The kimberlite pipeline on which the Williamson mining company is situated is the most crucial geological characteristic of the mine. It is the world’s largest financially exploitable diamond-manure volcanic pipe, with a surface area of 146 hectares. De Beers’ recent investigative drill cores revealed that the tube is indeed a pyroclastic kimberlite, which means it is not the previously thought hypabyssal kimberlite. This suggests that the present 90 m deep open-pit might be extended to 350 m, with subsurface mining activities continuing considerably deeper. However, the mine’s operations, as well as long-term plans, are still being reviewed.

Tanzania Diamonds Production

Today, the Williamson mining company has a poor ore grade of around 6 carats [1,200 milligrams] per hundred tonnes of the ore [12 mg/t]. The mean ore grade was approximately 30 carats [6.0 gram] per hundred tonnes [60 mg/t] in the first twenty-five years of production; in the beginning stages of full production, the mine produced up to 62 carats [12.4 gram] per hundred metric tonnes [124 mg/t], or 10 times what the ore realized at present. Output in the 1950s, as well as 60s, was generally between 500,000-carat diamonds and 750,000-carat diamonds [100 and 150 kilograms] annually; the apex year of manufacturing was 1966 because 924,984 carats [185 kilograms] were produced. All diamond pre-treatments activities at the Williamson mine currently produce around 300,000-carat diamond [60 kilograms] per year.

The 54.5-carat diamond [10.90 gram] Williamson pink gem was handed to then-Prince Philip and his spouse Princess Elizabeth for their marriage in 1947. A 388 carat [77.6 gram] diamond was discovered in 1990 are two notable stones mined from the Williamson quarry.


Tanzania’s diamond business in the early 1930s was characterized by a dispersion of small mining activities that had little impact on the country’s economy. In 1938, Dr. Williamson was recruited by one of these businesses, the Mabuki mining company, and he utilized it as a headquarters for diamond Tanzania exploration in the area. He located the Mwadui kimberlite pipeline in 1940, and during the next few years, he expanded the mine, despite difficulties obtaining equipment and generating funding due to WWII. By the early 1950s, he had turned the Williamson mining company into Tanzania’s first major diamond mine. The mining facility was visited by the American author John Gunther in the early 1950s, and he discusses it in his novel ”Inside Africa”. The mining company employed 2,600 Africans, 110 European workers, and 60 Asians at the time. Under Williamson’s leadership, the mine became known for technological advancements in diamond mining. Williamson was in charge of the quarry until he passed away in 1958. He was just 50 years old.

On the 13th of August 1958, Williamson’s heirs ultimately sold the mine to an equal collaboration involving the Tanganyika colonial government and De Beers for around 4 million Pounds. Tanzania’s authorities nationalized the Williamson mine in 1971, ten years after the country’s independence. Despite the lack of facts, De Beers, as well as other gemstone industry participants, believe that mine efficiency declined dramatically under government supervision in the 1980s. A decline in ore quality as the facility’s richer reserves were all worked out, the loss of qualified foreign engineering staff and their managerial skills, a swollen labor force as a result of government job creation efforts, and insufficient government funding in the mine’s production equipment are all suspected causes. Maybe as a reaction to these poor outcomes, the Tanzania Government persuaded De Beers to reinvest in the mining company, which they accepted. De Beers purchased 75 percent of the Williamson diamond mine in 1994, leaving Tanzania with the remaining 25%.

De Beers has taken steps to enhance the efficiency of the Williamson mining company since 1994, including reducing the workforce, investing in production equipment, as well as bringing in skilled professionals in technology, new techniques, and exploration. Despite the fact that the mine is currently considered a mediocre performer because of its poor ore quality, De Beers has discovered development opportunities that would allow the mine to continue operating in the future.

De Beers Diamond Consortium
De Beers Diamond Consortium

Petra Diamonds Limited agreed to buy the Williamson diamond mine Tanzania from De Beers in September 2008, and the deal was completed in February 2009.

After the drop in Tanzania diamonds prices in April of 2020, the facility was shut down.

Although Petra and the Tanzanian authorities agreed to reopen the mining facility in Q4 in February 2021, this didn’t come to pass.

Petra said in September 2021 that it was looking for investors for the mining facility. Confirming media stories from March 2021, when the mine was stated as permanently closed in the firm’s prospectus.


A variety of sporting amenities were available at the Tanzania diamonds mine. These featured a public swimming pool, tennis and squash courts, a soccer field, an athletic track, a golf course, and a yacht club. A surgical facility with two English and one Indian doctor as well as nursing personnel was also available. The healthcare center used to serve mine workers for free, and low-income individuals from the surrounding villages may pay a small fee to be treated there. After the colonial period, these structures crumbled, although the mine continues to preserve them in part.


2020 charges of human rights violations

In May 2020, a complaint was brought to the High Supreme Court of Wales and England for human rights abuses by guards. Since 2009, the NGO RAID has alleged proof of the damage done by paid guards who shot villagers on the property, including ten deaths and 50 injuries. Petra Diamond launched an internal inquiry in response to the news. During the stated window, internal investigations discovered only a single live-fire event, as well as additional instances of “appropriate force” towards illegal Tanzania diamonds miners.

Tanzania Diamond Market

The Tanzania diamond market is a significant contributor to the country’s economy. Tanzania is one of the top ten diamond producing countries in the world, with the Williamson diamond mine being the largest producer in the country. Other smaller mines also operate in Tanzania, although their production is comparatively limited.

The diamonds mined in Tanzania are typically of high quality, with a reputation for being well-formed and possessing excellent clarity.

One of the most sought-after types of diamonds mined is the pink diamond of Tanzania, which is highly prized by collectors and investors for its exceptional beauty and rarity. Pink diamonds are extremely rare, with only a small percentage of the world’s diamond production consisting of this type of stone. 

Another rare diamond is the Tanzania blue diamond, with only a small percentage of the world’s diamond production consisting of this type of stone. Blue diamonds get their color from the presence of boron during their formation, which creates a unique and striking blue coloration. 

Buying Diamonds in Tanzania

You’ll find multiple jewelry shops selling Tanzania diamonds. You’ll find plenty of Tanzania diamond rings and other sets of jewelry. 

The diamond ring price in Tanzania will depend on the weight. Here’s a chart on the diamond price per carat in Tanzania:

Diamond price per carat in Tanzania
Diamond price per carat in Tanzania


Are there diamond shipping services Tanzania

Yes, there are. Check out the diamond shipping services ltd Tanzania! 

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