Large, Exceptional Gem Diamonds Formed from Metallic Liquid inside Earth’s Mantle

"To date, researchers have puzzled over the origin of large diamonds like the famous Cullinan Diamond, discovered in South Africa in 1905; the Koh-i-Noor, found in India in the 13th century; or the widely publicized Lesedi La Rona stone, uncovered in Botswana in 2015. Historically, research into such diamonds has been nearly impossible due to the high value of the jewels and the fact that they rarely contain inclusions that might shed light on their geological origin."