Which mineral is the largest gem-quality diamond ever discovered?

The Cullinan Diamond is the largest gem-quality diamond ever discovered, weighing 3,106.75 carats in its rough form.

The diamond was found in 1905 at the Premier Mine near Pretoria, South Africa, and was named after mine owner Thomas Cullinan. The rough stone was presented to King Edward VII of the United Kingdom in 1907. It was later divided into several major polished stones.

The largest resulting gem is the Great Star of Africa, also called Cullinan I, weighing 530.2 carats. It is mounted in the Sovereign’s Royal Sceptre. Cullinan II, weighing 317.4 carats, is set in the Imperial State Crown.

“Largest” can mean different things in diamond discussions. The Cullinan remains the largest gem-quality rough diamond, while other stones may be compared by polished weight, colour, clarity, or value. It should not be confused with the Golden Jubilee, which became the largest polished diamond.