The Cullinan IV is in the private collection of Queen Elizabeth II of England, and its value, thus, is unknown.
According to Wikipedia:
"The Cullinan IV, a 63.60-carat cushion shape, was originally set in the band of Queen Mary's crown, but can also be worn as jewelry..."
Wikipedia estimates the value of the Cullinan 1 diamond at about $400 million. So combined the Cullinan 1 and Cullinan 2 are probably worth over $600 million.
Mother Nature made the Cullinan diamond, which was discovered by a human in 1905.
Thomas Cullinan - diamond magnate - died in 1936.
Thomas Cullinan - diamond magnate - was born in 1862.
The Cullinan was mined in South Africa, in 1905.
The Cullinan at more than 3,000 carats, remains the largest raw diamond ever found.
From Wikipedia: "The Cullinan diamond is the largest rough gem-quality diamond ever found, at 3,106.75 carats (621.35 g)."
According to Wikipedia: "The Cullinan diamond was found by Frederick Wells, surface manager of the Premier Diamond Mining Company in Cullinan, on January 26, 1905."
The Cullinan diamond was found in Africa in 1905. It was cut into several individual stones, the largest of which were named by appending Roman Numerals after Cullinan. You can read more about these diamonds, below.
First diamond, Cullinan I was called The First star of Africa/ Great star of Africa. You can review the link, below, and learn more about all the finished diamonds cut from the Cullinan.
The Cullinan was gifted to King Edward VII on his birthday by the Transvaal government which purchased it from the Premier Diamond Mining company in Cullinan, South Africa. You can read more about its continued history, below.
The Cullinan, found in the early 1900s, was gifted to Queen Victoria. You can read more about its disposition, below.