The Cullinan Diamond

Contributed by David Buckerfield

South Africa: The Cullinan Diamond
The Cullinan Diamond
The 'Big Hole'
The Cullinan Diamond is the largest rough gem-quality diamond ever discovered. At 3,106 carats (621 grams) it was almost as big as a man's fist. There is a life-size glass replica.

It was found in the 'big hole' of the Premier Diamond Mine, located in Cullinan, East of Pretoria, the capital of South Africa, at the beginning of the Twentieth Century. Folklore stories abound in connection with large mining finds; it was rumoured that the diamond was found right next to the discoloured rock pattern in the centre of this photograph - a discolouration that is roughly heart-shaped! The credit for finding the diamond was given to the miner Thomas Evan Powell who found it on January 26, 1905. He received a substantial award for his find (and his honesty in handing it over). The mine and the diamond were named after Sir Thomas Cullinan, the original mine owner.

The Cullinan Diamond
Sir Thomas Cullinan
The Transvaal government bought the rough diamond from the mine for 150,000 pounds. Transvaal Prime Minister Louis Botha's proposal to give the Cullinan to King Edward VII was approved by the Transvaal Parliament and the rough diamond was accepted by the King in a 66th birthday presentation on 9th November 1907. It must be remembered that this was a period very shortly after the Boer War which had led to much bitterness between the Boers and the British. It was thought that this gesture might help reconcile the two sides to a certain extent.

Transporting it from South Africa to England caused much anxiety to the authorities. In a novel plan, detectives from London were placed on a steamboat that was rumoured to carry the stone. The stone on that ship was actually a fake, meant to attract those who would be interested in stealing it. The actual diamond was sent to England in a plain box via parcel post, albeit registered!

The Crown Jewels
The Cullinan Diamond
Replicas of the Stones
The British authorities awarded the Amsterdam firm of I. J. Asscher and Company the order to cut the stone. Mr. Joseph Asscher, the firm's principal, studied the stone for three months, assessing the stress fault and the optimum facets on which to cut. His first strike broke the cutter blade, mercifully with no damage to the diamond. His second stroke was perfect and split the stone as planned along the fault line. It was reported that Mijnheer Asscher promptly fainted with relief, though this account of events is disputed! The two stones were then further cleaved into nine major stones plus a large number of smaller stones.

You can see a collection of replica cut stones against a replica of the uncut stone here

The nine originals are classed as Flawless and form part of the British Crown Jewels, with the 530 carat 'Star of Africa' topping the Sovereign's Royal Sceptre. It is also known as the Cullinan 1 diamond and it is approximately the same size and shape as a regular chicken egg.

The 'Second (or Lesser) Star of Africa' is 317 carats, and it adorns the Imperial State Crown. It is sometimes called the Cullinan 2 diamond.

Premier Diamond Mine
The Cullinan Diamond
Premier Mine
The mine currently produces about 1,000,000 carats of diamonds annually which is not a particularly high yield. 1 carat = 200 mg, therefore 1,000,000 carats is the equivalent of 200kg. Approximately 80% of the output comprises industrial diamonds, with the remaining 20% being of gem quality diamonds. Nowadays, it employs just 1,200 people. The mine was sold to Petra Diamonds by De Beers in 2008.

The mine has produced other notable diamonds over the years such as the 545 carat Golden Jubilee and the 273 carat Millennium Star.

More recently a rare blue diamond of just 7.03 carats from the Premier Mine smashed the all time price per carat record when the buyer paid over 9.4 Million dollars for it in 2009. The new owner named it the 'Star of Josephine'.

Mine Tour
Why visit the mine?
  • This single mine has produced over 25% of all the 400+ carat diamonds ever found- it thus has a truly unique record.

  • It is only operational during normal weekdays, so it is clean & quiet at weekends, when only maintenance and admin staff are on duty.

  • Two tours are available; underground plus surface or surface only.

  • The mine has its own museum. The glass replica diamonds shown above are on display there.

  • There is a shop, plentifully stocked with magnificent cut diamonds.

  • In a corner of the shop a diamond cutter works and displays his craft and this is fascinating to watch.

  • The diamonds on display carry Premier's trademark, the Cullinan Star Cut.

  • There are zero restrictions on photography (at least this was the case when I visited the mine in 2009).

    The Cullinan Diamond
    I opted for the mine surface tour which starts with a 10 minute video and this is followed by a guided walking tour.

    Here, you can see the entrance to the mine compound.

    Diamonds are formed at a depth of 120 to 200 km below the earth's surface and they are 100% carbon. The right combination of temperature, pressure & chemistry can lead to carbon atoms bonding and crystallising in to diamonds.

    If diamonds are found in river beds & estuaries the type of mining process is called alluvial. Inland mining requires kimberlite pipes to bring the diamonds to the surface, usually by means of a volcano. The Premier Diamond Mine is situated atop an extinct volcano.

    The winder moves the ore-carrying skips up and down the mineshaft via the headgear.

    Spare skips are ready to be installed when needed.

    All the mining is underground nowadays. The workings are down to 800 metres below the surface and there are 700 km of shafts & tunnels!

    The Cullinan Diamond
    Old Mining Machinery
    The mine shop kindly lets you know what to look for when buying a diamond. They provide all sorts of charts to help you understand the intricacies of the high-end diamond industry.

    The surface tour took about 90 minutes and I found it most interesting and well presented. The cost was ZAR 60 (approximately 5.50 pounds sterling).

    Outside the mine there are static exhibits of some weird and wonderful examples of old mining machinery.

  • Cullinan Town
    The Cullinan Diamond
    Local Architecture
    I've noticed in some literature that Cullinan is still described as a village, but it has definitely grown in to a small town over the years. It has pleasant tree lined streets.

    It's also a very laid back town and it's a pleasure just to stroll around.

    Much of the architectural style is original or pseudo Victorian and Edwardian. Cafes and gift shops abound.

    A visit to Cullinan and the diamond mine seems like stepping back in time and makes for a pleasurable day trip.

    The Cullinan Diamond
    Transvaal Colony Profile
    I found this to be one of the most informative websites available to anyone wishing to buy diamonds:
    About Diamond Cuts.
    Also by David Buckerfield
    Anglo-Zulu War
    Churchill's Capture

    Armed Forces | Art and Culture | Articles | Biographies | Colonies | Discussion | Glossary | Home | Library | Links | Map Room | Sources and Media | Science and Technology | Search | Student Zone | Timelines | TV and Film

    by Stephen