It was found in a mine in Karowe, in Botswana 430 km from the capital Gaborone, the Second largest rough diamond in the worldwith a weight of 2,492 caratsequal to approximately 468 gramsThe Canadian mining company announced this Lucara Diamondwho discovered diamond through technologies based on X-ray transmission (XRT), an advanced technique that allows the isolation of precious gems by analyzing their density and shape.
The world record is still held by Cullinan Diamonddiscovered in 1905 in the Premier Mine in South Africafrom the weight of 621.2 grams equal to 3,106 carats and rated over 400 million dollars. It was later cut into 9 large and 100 smaller gems, which today form an integral part of the British royal regalia.
The discovery of the rough diamond
The discovery was announced on August 21, 2024 on the website of Lucara Diamond, the mining company that operates the Karowe minelocated in the North-East Botswanathe place where the diamond was found. The rough stone weighs 2,492 carats and is large enough to fill the palm of an adult’s hand. The economic value has not yet been defined, but it is estimated that it could reach several tens of millions of US dollars.
“We are thrilled with the discovery“, – he declared William LambCEO of Lucara Diamond. “This find not only shows the great potential of the Karowe mine, but also supports our strategic investment in cutting-edge XRT technology.“The discovery, in fact, was made possible by the use of the Mega Diamond Recovery (MDR)a technique already used for several years in the mining industry which allows identify and isolate precious gems based on their density and shape, thus facilitating the extraction of large stones and minimizing the risk of damaging them or break them.
The use of this technology has already proven effective in the past at the Karowe mine. In 2019, in fact, the Sewelô diamondat the time considered the second largest diamond in the world, weighing 352 grams and a total of 1,758 caratsand an estimated value higher than 19 million dollars. In 2015, the diamond was found in the same mine Read the Ronaweighing 1,109 carats, which was purchased by a British jeweler for 53 million dollars in 2017.
In addition to being the largest ever mined in Botswana, the Karowe diamond is the second largest ever found in the world And the largest discovered in over a century.
How X-ray XRT Technology Works
The XRT approach takes advantage of the different capacity of X-ray absorption of different minerals, which is determined by their atomic density; this, in turn, depends on the chemical composition and from the crystal lattice structurethat is, from the arrangement of the atoms in the space that constitutes the mineral. Diamond, which is made up only of carbon atomsabsorbs relatively less X-ray radiation than other minerals in the same rocks, which may be rich in soccer, silicon, magnesium, iron, oxygen and other heavier elements. Diamond’s lower ability to absorb X-rays is due to its lower atomic density, or lower number of atoms per unit volume.
In the technique used in the Karowe mine, fragments of kimberlitethe igneous rocks from which diamonds are mined in the area, are evenly distributed on a conveyor belt and passed under a X-ray source. A sensor detects the amount of radiation absorbed. A computer then processes the data and creates an image of the minerals present in the rocks by dividing them based on their chemical composition, shape and density. If the density detected is similar to that of diamond, at the end of the conveyor belt a jet of air pushes the selected mineral into a collection container.
