Gem Diamonds
Corporate brand
UnclaimedGem Diamonds is a London-based diamond mining company focused on high-value rough diamonds, particularly large and exceptional stones from its Letšeng mine in Lesotho.
Last updated August 22, 2026
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Overview
Gem Diamonds is a United Kingdom-based diamond mining company headquartered in London and listed on the London Stock Exchange under the ticker GEMD. Founded by Clifford Elphick in July 2005, the business developed a mining portfolio centered on southern Africa and built its reputation around the recovery of unusually large, high-quality rough diamonds rather than bulk production alone. The company’s defining asset is the Letšeng diamond mine in Lesotho. Gem Diamonds acquired the mine in 2006, and Letšeng subsequently became associated with some of the world’s most valuable large white gem-quality diamonds. The operation has been described as the highest dollar-per-carat kimberlite diamond mine in the world. Its production profile is unusual: Letšeng is not primarily known for the largest volume of diamonds, but for the exceptional value and rarity of selected stones recovered from its ore. Several major Letšeng discoveries have weighed more than 100 carats, and some have been sold to prominent luxury jewelry houses, including Graff Diamonds. Among the mine’s best-known discoveries is the 603-carat Lesotho Promise, announced in 2006. In January 2018, Letšeng produced the 910-carat Lesotho Legend, described as the fifth-largest gem-quality diamond ever discovered. The stone was sold in Antwerp in March 2018 to Samir Gems for $40 million. Later in the first quarter of 2018, the company also reported recovering a 169-carat, top-white-color Type IIa diamond. These discoveries reinforced Gem Diamonds’ positioning as a specialist producer of large, high-purity and high-color rough diamonds. Gem Diamonds also pursued exploration and development in Botswana. In 2007, it began diamond prospecting on traditional lands associated with the San, or Bushmen, communities. The company later developed the Ghaghoo project, located within the Central Kalahari Game Reserve, with construction of the first phase beginning in 2011. The project became controversial because of concerns about consultation with Indigenous communities, alleged displacement, and the compatibility of mining activity with a protected area established for wildlife and the communities historically dependent on the land. These issues formed an important part of public scrutiny of the company’s Botswana activities. The company’s business model combines mine development, rough-diamond recovery, sorting and sales. Its commercial identity is closely linked to the scarcity premium attached to exceptional stones, while its operating and financial performance remains exposed to diamond prices, rough-diamond demand, recovery grades, geological variability, mining costs, safety conditions and the regulatory environments of its host countries. Gem Diamonds is therefore best understood as a specialist listed mining company rather than a consumer jewelry brand. Its principal offering is uncut natural diamond production, with Letšeng serving as its flagship operation. Reference material identifies operations in Lesotho and Botswana. The company’s public profile has been shaped by the Letšeng mine, the development history and controversy surrounding Ghaghoo, and a series of notable large-diamond recoveries. A later reported Letšeng recovery in 2026 comprised a 104.73-carat Type IIa white diamond and a 151.52-carat yellow diamond; the timing and details of that report should be checked against current company disclosures.
History
Gem Diamonds was founded in July 2005 by Clifford Elphick as a United Kingdom-based diamond mining company. From the beginning, its strategy was oriented toward the exploration, development and operation of diamond assets with the potential to produce valuable rough stones. Rather than positioning itself as a jewelry manufacturer or retail brand, the company operated upstream in the diamond supply chain, selling uncut stones to specialist buyers and the broader international diamond market. A decisive turning point came in 2006, when Gem Diamonds acquired the Letšeng diamond mine in Lesotho. Letšeng became the company’s signature asset and the foundation of its specialist reputation. The mine is notable for producing relatively rare, large and high-quality diamonds from kimberlite ore. After the acquisition, Gem Diamonds announced the discovery of the 603-carat Lesotho Promise. The stone helped establish the company as a producer capable of recovering exceptional diamonds and drew attention to Letšeng’s unusually high value per carat. Gem Diamonds became publicly listed on the London Stock Exchange in 2007. Listing provided a public-market structure for financing and governing its mining activities while exposing the company to the volatility of rough-diamond prices, production results and investor expectations. In the same year, the company began diamond prospecting in Botswana on lands traditionally associated with San communities. This activity led to criticism from Survival International and other observers, who questioned whether affected communities had been adequately consulted and raised concerns about displacement from traditional lands. The Botswana strategy developed into the Ghaghoo mine project. Construction of its first phase began in 2011, approximately 45 kilometres inside the eastern boundary of the Central Kalahari Game Reserve. The project was controversial because the reserve was associated with wildlife conservation and with the historical homeland and subsistence practices of the San. Critics argued that mining development could compound the effects of earlier removals and that consultation and consent issues had not been sufficiently addressed. The Ghaghoo episode placed Gem Diamonds within wider debates about resource extraction, protected areas, Indigenous rights and the responsibilities of mining companies operating in politically sensitive regions. Letšeng remained the central source of the company’s public identity. The mine subsequently yielded several stones larger than 100 carats, including five of the 20 largest known white gem-quality diamonds cited in the company’s history. Several notable Letšeng stones were purchased by Graff Diamonds, illustrating the connection between Gem Diamonds’ upstream production and the high-end jewelry sector. In January 2018, Letšeng produced the 910-carat Lesotho Legend, described as the fifth-largest gem-quality diamond ever found. The stone was sold in Antwerp on 12 March 2018 to Samir Gems for $40 million. During the first quarter of that year, the company also announced recovery of a 169-carat top-white-color Type IIa diamond, reported as its seventh stone above 100 carats from the mine. The company’s economic performance has depended on the interaction of exceptional-stone recoveries and ordinary mining fundamentals. Large discoveries can materially influence revenue and brand recognition, but they are inherently irregular. Costs, grades, recoveries, mine development, labor and safety, host-country regulation, environmental obligations and the global diamond market all affect results. A reference source reports a 2017 profit of $20.8 million, although the accounting basis should be checked against the relevant annual report before use in financial analysis. Reference material identifies Gem Diamonds’ operations in Lesotho and Botswana. Its enduring corporate narrative is therefore built around two contrasting elements: Letšeng’s globally recognized record of exceptional diamond production and the social and environmental controversy surrounding exploration and mine development in Botswana. A later reference reports that Letšeng recovered a 104.73-carat Type IIa white diamond and a 151.52-carat yellow diamond in 2026; those details require confirmation from current primary disclosures.
- 2018
Lesotho Legend recovered and sold
[1]Letšeng produced the 910-carat Lesotho Legend, which was sold in Antwerp for $40 million.
- 2011
Ghaghoo construction begins
[1]Construction of the first phase of the Ghaghoo mine began inside Botswana’s Central Kalahari Game Reserve.
- 2007
London Stock Exchange listing
[1]Gem Diamonds was listed on the London Stock Exchange.
- 2007
Botswana prospecting begins
[1]The company began diamond prospecting on traditional San lands in Botswana.
- 2006
Letšeng acquired
[1]Gem Diamonds acquired the Letšeng diamond mine in Lesotho, which became its principal operating asset.
- 2006
Lesotho Promise discovered
[1]A 603-carat diamond was recovered at Letšeng and became known as the Lesotho Promise.
- 2005
Company founded
[1]Gem Diamonds was founded in July 2005 by Clifford Elphick.
Products and positioning
A specialist producer of large, high-quality and high-value rough diamonds, with Letšeng in Lesotho as its signature asset.
Diamond mining · 2006
Letšeng rough diamonds
Rough natural diamonds recovered from the Letšeng mine in Lesotho form Gem Diamonds’ principal commercial output. Letšeng is distinguished by the frequency and value of unusually large, high-quality stones, including white gem-quality and Type IIa diamonds. Production is sold into the international rough-diamond market, where exceptional stones may be offered through specialist sales or acquired by luxury jewelry companies.
High-value rough diamonds · 2006
Exceptional large diamonds
The company’s most prominent product category is the occasional recovery of very large stones. Notable examples include the 603-carat Lesotho Promise, the 910-carat Lesotho Legend and a 169-carat Type IIa diamond reported in 2018. These stones are not standardized consumer products; their value depends on size, color, clarity, type, market conditions and the eventual cutting and polishing strategy selected by the buyer.
Diamond mining · 2011
Ghaghoo mine production
Ghaghoo was a Botswana diamond-mining development associated with Gem Diamonds’ exploration and construction activities. The project was located within the Central Kalahari Game Reserve and became notable not only as a mining undertaking but also because of disputes and criticism concerning Indigenous rights, consultation, displacement and protected-area governance.
Controversies
2011
Ghaghoo development controversy
Construction of the Ghaghoo mine inside the Central Kalahari Game Reserve generated controversy over mining in a protected area and the potential effects on San communities and wildlife. The available reference material describes the dispute and allegations but does not establish a legal finding against Gem Diamonds.
2007
Concerns over prospecting on traditional San lands
Gem Diamonds’ Botswana prospecting activities attracted criticism from Survival International, which alleged that consultation with San communities had been insufficient and connected the project to the forced removal of people from traditional lands. The allegations formed part of a broader dispute involving government policy, Indigenous rights and resource development.
Brand decisions
2018
Sale of the Lesotho LegendOtherBackground
The recovery of a 910-carat gem-quality diamond created an opportunity to monetize an unusually valuable Letšeng stone.
Action taken
The Lesotho Legend was sold in Antwerp to Samir Gems on 12 March 2018.
Aftermath
The reported sale price was $40 million and strengthened Letšeng’s reputation as a source of exceptional diamonds.
Sale price. $40 million (12 March 2018)
2011
Development of the Ghaghoo mineProduct launchBackground
Gem Diamonds advanced its Botswana exploration portfolio toward mine construction.
Action taken
Construction of the first phase of Ghaghoo began inside the Central Kalahari Game Reserve.
Aftermath
The project became a focus of public debate about protected-area mining and the rights of San communities.
2007
Expansion into Botswana prospectingStrategyBackground
The company pursued additional southern African exploration opportunities beyond its Letšeng asset.
Action taken
Gem Diamonds began prospecting on traditional San lands in Botswana.
Aftermath
The strategy led to the Ghaghoo development but also attracted criticism concerning consultation, displacement, conservation and Indigenous rights.
2006
Acquisition of LetšengM&ABackground
Gem Diamonds sought to build a diamond-mining portfolio with exposure to high-value southern African assets.
Action taken
The company acquired the Letšeng diamond mine in Lesotho.
Aftermath
Letšeng became the company’s flagship operation and the source of multiple exceptional large diamonds.
Sources2 sources
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