26 January: The Cullinan Diamond

On this date in 1905 The world's largest diamond, "The Cullinan" was discovered in the Premier Mine, Pretoria, South Africa.

Not the Cullinan Diamond, just a random one

1. Most of the sources I looked at said the diamond was found by mine superintendent Frederick Wells during a routine inspection, and that he extracted it using a pocket knife. One source, however, said it was found by a miner called Thomas Evan Powell who brought it to Wells' attention.
2. Either way, it was still the largest uncut diamond ever found up to that point, weighing 3,106.75 carats (621.35 g). It held the record until 1985 when the Golden Jubilee Diamond was found at the same mine. The Golden Jubilee Diamond weighs in at (545.67 carats (109.13 g).
3. It was named after the mine's chairman, Thomas Cullinan.
4. Sir William Crookes performed an analysis of the Cullinan diamond. His observation was that it was remarkably clear although it had a black spot in the middle surrounded by vivid colours. This, he said, was due to internal strain, which isn't uncommon in diamonds. One side of it was perfectly smooth, which suggested it had once been part of an even bigger diamond which was probably over twice the size. The other parts were probably still in the mine somewhere, he said, and "await discovery by some fortunate miner."
5. According to legend, Frederick Wells broke off a 300-400g piece of the diamond before it left the mine.
6. The Transvaal Colony government bought the diamond for £150,000 and insured it for ten times that amount. The Prime Minister of the time, Louis Botha, suggested giving it to King Edward VII as "a token of the loyalty and attachment of the people of the Transvaal to His Majesty's throne and person". Not everyone agreed with him, although a majority voted in favour. The British Prime Minister of the time, Henry Campbell-Bannerman, decided the king himself should decide whether to accept it or not. Winston Churchill, however, persuaded the king he should take it. The king gave Churchill a replica of the diamond which it's said he liked to put on a Silver plate to show to his friends.
7. The diamond was sent to England via parcel post. Registered post, admittedly, but by post nonetheless. Sir Francis Hopwood and Mr Richard Solomon (Agent-General of the Transvaal government in London) then took it to Sandringham by train with just two experienced Scotland Yard policemen. That may not sound very secure - however, there was a decoy. A parcel containing a fake diamond was ceremoniously placed in the safe of a steamboat and guarded by detectives during the journey.
8. The diamond was eventually cut up into nine large stones and some smaller ones. The job of cutting it went to Asscher Brothers of Amsterdam's expert diamond cutter, Joseph Asscher. There's a legend that Joseph was so over-awed at the thought of cutting the largest diamond ever known that he fainted after making the first cut. However, people who knew him disputed that he'd have done any such thing - he was far more likely to have cracked open a bottle of Champagne.
9. The largest of the fragments is Cullinan I, or the Great Star of Africa, which weighs 530.2 carats (106.04 g) and is 5.9-centimetres (2.3 in) long. It is the largest clear cut diamond in the world. It is set at the top of the Sovereign's Sceptre with Cross which had to be redesigned in 1910 to accommodate it. It can be removed from the sceptre and made into a brooch along with the next largest piece, Cullinan II, or the Second Star of Africa, which is set in the front of the Imperial State Crown.
10. Cullinan III and IV are both referred to as the Lesser Star of Africa. Both these stones were set into a crown for Queen Mary, wife and queen consort of George V, to wear for her coronation. They were removed from the crown in 1914 and are now worn by Queen Elizabeth II as a brooch. She revealed in 1958 that the royal family referred to these diamonds as "Granny's Chips". She wore them on a visit to the Asscher Diamond Company, where she allowed Louis Asscher, Joseph's brother, to examine them, fifty years after the diamond was cut.