Audience versions of this page: FamilyOn January 26, 1905, miners in South Africa unearthed the Cullinan diamond, the largest gem-quality diamond ever discovered.Diamonds are minerals that form from an unusual type of magma, called kimberlite, deep in Earth’s mantle. Kimberlite forms in a deeper area of the mantle, is subjected to greater pressure, and contains more water and carbon dioxide than most magmas. Diamonds form as kimberlite violently erupts on Earth’s surface.The Cullinan diamond, a whopping 3,106 carats and weighing about 621 grams (1.4 pounds), was cut into nine stones. The largest, nicknamed Cullinan I or the “Great Star of Africa,” is 530 carats. Today, the Great Star of Africa sits at the top of a scepter, part of the Crown Jewels of the United Kingdom.
Term Part of Speech Definition Encyclopedic Entry carat Noun
unit of weight, used for gems, about 200 milligrams.
type of crystal that is pure carbon and the hardest known natural substance.
to explode or suddenly eject material.
mineral, rock, or organic material that can be cut and polished for use in jewelry.
type of magma or igneous rock associated with diamonds.
molten, or partially melted, rock beneath the Earth's surface.
Encyclopedic Entry: magma mantle Noun
middle layer of the Earth, made of mostly solid rock.
Encyclopedic Entry: mantle miner Noun
person who excavates metal or other materials from the Earth.
inorganic material that has a characteristic chemical composition and specific crystal structure.
natural substance composed of solid mineral matter.
symbolic staff or rod carried by a monarch or other ruler.