QUEEN ELIZABETH II, 94, is one of the wealthiest women in the world. She also owns a diamond brooch made from the largest stone of quality ever found. Exactly how much is it worth?

Our expert Alexandra Michell, Gemologist told Express.co.uk all about this fascinating gem and how it came to the British Royal Family.

She said: “In 1905, Frederick Wells, surface manager of Premier Mines in South Africa, discovered the largest gem quality diamond in history; The Cullinan. Weighing a staggering 3106cts, this incredible rough diamond is said to only be a portion of a much larger diamond, although it has yet to be discovered.

“It was presented a few hours later to the mines’ owner, Sir Thomas Cullinan.

“The sale of the stone was negotiated and purchased by the Transvaal Government at £150,000 in 1907 (now roughly £18,000,000) with a view of gifting it to King Edward VII as a birthday present, as well as a gesture of loyalty to Great Britain.”

Check out our selection of pre-owned brooches.