Miners in the southern African kingdom of Lesotho have found one of the world's largest diamonds, a near-flawless white gem¹ weighing nearly 500 carats, mining group Gem Diamonds said on Sunday.

The diamond was discovered in the Letseng Mine on September 8, the company said in a statement. It has been analyzed² by experts in Antwerp and found to weigh 478 carats, with very few inclusions and of outstanding color and clarity.

"It has the potential to yield one of the largest flawless D color round polished diamonds in history," the company said.

Letseng is one of the most productive mines in history -- four of the world's 20 largest rough diamonds have been found at the mine, including the three largest found this century.

Before it is cut into gems³ it is hard to value the diamond, but a spokesman for Gem Diamonds said a similar weight stone with lesser-quality color and clarity had recently sold for $12 million (around 5.5 million pounds).

"Preliminary examination of this remarkable⁴ diamond indicates that it will yield a record breaking polished stone of the very best color and clarity," Clifford Elphick, the chief executive of Gem Diamonds, said in a statement.

The minister for natural resources in Lesotho praised the productivity of the mine, one of the highest in the world at more than 3,000 meters (10,000 feet).

"Once again Letseng has proved its ability to produce extraordinary diamonds and continues to place Lesotho at the forefront of diamond producing countries," Monyane Moleleki said in a statement.

The world's largest diamond is the Cullinan, discovered in South Africa in 1905. It weighed more than 3,100 carats before it was cut into more than one hundred separate gems, many of which are part of the British crown jewels.

（英国）杰姆钻石公司于上周日称，日前他们在非洲南部的莱索托王国发现了一颗世界上最大的钻石。这颗白钻近乎无暇，重近500克拉。

杰姆钻石公司在一份声明中称，这颗钻石于本月8日在莱索托的莱特森矿发现。经（比利时）安特卫普的专家们鉴定，这颗钻石重达478克拉，含极少杂质，色泽和纯净度都极佳。

据该公司介绍：“它有望被打造成历史上最大的、无暇D级色泽圆形抛光钻石之一。”

莱特森矿是历史上产量最高的钻石矿之一。目前全球20颗最大的原钻中有四颗产自这里，其中有三颗发现于本世纪。

钻石在切割前很难估价，但据杰姆钻石公司的一位发言人介绍，一颗类似重量、色泽和纯净度稍逊的钻石最近以1200万美元（550万英镑）的价格售出。

公司首席执行官克里福德•艾尔菲克在一份声明中说：“初步鉴定结果表明，这颗钻石抛光后，其色泽和纯净度有望达到破纪录的等级。”

莱特森矿海拔3000多米（1万英尺），是世界上地势最高的钻石矿之一。莱索托自然资源大臣高度评价了它的生产能力。

蒙莫尼亚内•莫莱莱基在一份声明中说：“莱特森矿再次证明了其出产非凡钻石的能力，并巩固了莱索托钻石出产大国的地位。”

目前全球最大的钻石是1905年在南非发现的一颗名为“Cullinan”的原钻。这颗原钻重量超过3100克拉，之后被切割成100多颗小钻，其中很多被用在了英国女王的王冠上。