You own a diamond. You know its carat weight. You may have compared it to other diamonds of similar size and found wildly different prices. You may have heard about the largest diamond ever found — the Cullinan — and wondered what it can tell you about your own piece. You want to understand what actually determines diamond value.
Bigger diamonds are worth more. Carat weight is the most important factor. The Cullinan is the largest, so it must be the most valuable.
"What characteristics of your diamond — beyond carat weight — would a buyer actually care about?"
If you have a GIA certificate, look beyond the carat line. The clarity and cut grades often matter more to a buyer than the weight. If you do not have a certificate, understand that carat weight is the only verifiable fact you have right now — everything else is assumption.
The Cullinan Diamond, discovered in 1905 at the Premier Mine in South Africa, weighed 3,106 carats in the rough — about 621 grams, roughly the size of a human fist. It was cut into 9 major stones and 96 smaller stones. The largest finished stone, the Cullinan I or Star of Africa, weighs 530.2 carats and is set in the British Sovereign's Sceptre with Cross.
No. Carat weight is only one of four globally recognized quality factors — along with clarity, color, and cut. A 1-carat diamond with exceptional clarity (FL-IF), colorless grade (D-F), and excellent cut can be worth far more than a 3-carat diamond with visible inclusions, noticeable color, and poor cut. Weight measures quantity. The other three Cs measure quality. Value depends on all four.
The Cullinan Diamond is part of the British Crown Jewels and is considered priceless — it will never be sold. Insurance estimates have placed its value in the hundreds of millions, but there is no market price because there is no market for it. This illustrates an important point: some diamonds derive their significance from history and context, not from what a buyer would pay.
The Cullinan was discovered on January 26, 1905 by Frederick Wells, a surface manager at the Premier Mine in South Africa. He spotted it 18 feet below the surface during a routine inspection. It was named after Sir Thomas Cullinan, the owner of the mine. The diamond was purchased by the Transvaal government and presented to King Edward VII of the United Kingdom in 1907.
The cutting was entrusted to Joseph Asscher of Amsterdam, one of the most renowned diamond cutters of the era. After studying the stone for months, Asscher made the first cleavage strike in February 1908 — and reportedly fainted immediately afterward, even though the cut was successful. The stone was ultimately divided into 9 major gems (Cullinan I through IX) and 96 smaller brilliants, a process that took over 8 months.
