The worlds top diamonds

The De Beers Centenary Diamond is, at 273.85 carats (54.770 g), the third-largest diamond to have been produced in the Premier Mine. Among top-colour diamonds, only the Cullinan I and II are larger than the Centenary diamond.

The Centenary Diamond is rated in colour as grade D colour by the Gemological Institute of America, which is the highest grade of colourless diamond and is internally and externally flawless. It was named the Centenary Diamond as it was presented in the rough for the Centennial Celebration of De Beers Consolidated Mines on May 11, 1988. The Centenary Diamond was unveiled in final form in May 1991.

The Centenary Diamond was discovered in the Premier Mine on 17 July 1986 using their X-ray imaging system. The original rough was 599 carats (119.8 g) and it was presented on 11 May 1988 in the Centennial Celebration of the De Beers Consolidated Mines. As then-chairman Julian Oglivie Thompson said, "We have recovered at the Premier Mine a diamond of 599 carats (119.8 g) which is perfect in colour – indeed it is one of the largest top-colour diamonds ever found. Naturally it will be called the Centenary Diamond."

The Centenary was completed in February 1991, weighing 273.85 carats (54.770 g) with its dimensions measuring 39.90 × 50.50 × 24.55 mm. The final gem had 247 facets: 164 on the pavilion and crown, and 83 on the girdle. While the stone has never been publicly appraised for value, it is known to have been insured at over US$100 million at the time of its unveiling in May 1991. The stone was loaned to the Tower of London, where it was displayed for a number of years. It is believed that De Beers no longer owns the Centenary, but the current owner is unknown. De Beers declines to comment, citing its anonymity policy.

Cutting such an immense and valuable diamond required expertise and a considerable investment. Gabi Tolkowsky was chosen to head the team responsible for cutting the Centenary Diamond, along with Geoff Woolett, Jim Nash and Dawie du Plessis, assisted by a specially picked group of engineers, electricians and security guards to facilitate in the work on Centenary Diamond.

There was a special room designed underground in the De Beers Diamond Research Laboratory in Johannesburg, South Africa for the sole purpose of working on the Centenary Diamond with design specifications including strength and stability so as to preclude mechanical vibration and temperature variation to minimise any factor that might interfere with the cutting of the Centenary Diamond.

The initial efforts were done by hand rather than with a laser or saw so as not to heat or vibrate the diamond. After cutting and removing 50 carats (10 g) of cracked material over 154 days, the team was left with an egg-shaped gem of approximately 500 carats (100 g). Thirteen different designs were presented to the De Beers board, with a strong recommendation for what became the eventual modified heart-shaped design.

The shape was described as, "Effectively, the Centenary Diamond is shaped like a heart-shape, but it does not have a groove. The image the team had in mind was a shape which would adorn the turban of a Sultan or a Maharaja."

The Hope Diamond is one of the most legendary jewels of history, with ownership records dating back almost four centuries. Its much-admired rare blue colour is due to trace amounts of boron atoms. Weighing 45.52 carats, its exceptional size has revealed new findings about the formation of gemstones.

The jewel is believed to have originated in India, and is known to have been cut from the French Blue (Le bleu de France), presented to King Louis XIV. It acquired its name when it appeared in the catalogue of a gem collection owned by a London banking family called Hope in 1839. Later it was sold to Washington socialite Evalyn Walsh McLean who was often seen wearing it. Since 1958, it has been on exhibition at Washington’s National Museum of Natural History.

The Hope Diamond has long been rumoured to carry a curse, possibly due to agents trying to arouse interest in the stone. It was last reported to be insured for $250 million.

The Hope Diamond, also known as Le Bijou du Roi ("the King's Jewel"), Le bleu de France ("The Blue of France"), and the Tavernier Blue, is a large, 45.52-carat (9.104 g), deep-blue diamond, and now housed in the National Gem and Mineral collection at the National Natural History Museum in Washington, D.C. It is blue to the naked eye because of trace amounts of boron within its crystal structure, and exhibits red phosphorescence after exposure to ultraviolet light.

It is classified as a Type IIb diamond, and has changed hands numerous times on its way from India to France to Britain and eventually to the United States, where it has been regularly on public display since. It has been described as the "most famous diamond in the world"

The Hope Diamond was formed deep within the Earth approximately 1.1 billion years ago. Like all diamonds, it is formed when carbon atoms form strong bonds.

The Hope Diamond was originally embedded in a kimberlite and was later extracted and refined to form the brilliant gem it is today. The Hope Diamond contains trace amount of boron atoms intermixed with the carbon structure, which results in the rare blue colour of the diamond

Weight. In December 1988, the Gemological Institute of America's Gem Trade Lab determined that the diamond weighed 45.52 carats (9.104 g; 0.3211 oz).

Size and shape. The diamond has been compared in size and shape to a pigeon egg, walnut, a "good sized horse chestnut" which is "pear shaped."

The dimensions in terms of length, width, and depth are 25.60 mm × 21.78 mm × 12.00 mm (1 in × 7/8 in × 15/32 in).

Colour. It has been described as being "fancy dark greyish-blue" as well as being "dark blue in colour" or having a "steely-blue" colour.

Clarity. The clarity was determined to be VS1, with whitish graining present.

Cut. The cut was described as being "cushion antique brilliant with a faceted girdle and extra facets on the pavilion.

Touch and feel. When Associated Press reporter Ron Edmonds was allowed by Smithsonian officials to hold the gem in his hand in 2003, he wrote that the first thought that had come into his mind was: "Wow!" It was described as "cool to the touch."

The Koh-i-Noor (Persian for Mountain of Light; also spelled Koh-i-Nûr and Kooh-è Noor) is a large, colourless diamond that was found near Guntur in Andhra Pradesh, India, possibly in the 13th century. It weighed 793 carats (158.6 g) uncut and was first owned by the Kakatiya dynasty. The stone changed hands several times between various feuding factions in South Asia over the next few hundred years, before ending up in the possession of Queen Victoria after the British conquest of the Punjab in 1849.

In 1852, Prince Albert, the husband of Queen Victoria, unhappy with its dull and irregular appearance, ordered it cut down from 186 carats (37.2 g). It emerged 42 per cent lighter as a dazzling oval-cut brilliant weighing 105.6 carats (21.12 g) and measuring 3.6 cm x 3.2 cm x 1.3 cm.

By modern standards, the cut is far from perfect, in that the culet is unusually broad, giving the impression of a black hole when the stone is viewed head-on; it is nevertheless regarded by gemmologosts as being full of life.[4] As the diamond's history involves a great deal of fighting between men, the Koh-i-Noor acquired a reputation within the British royal family for bringing bad luck to any man who wears it. Since arriving in the country, it has only ever been worn by female members of the family.

Today, the diamond is set in the front of the Queen Mother's Crown, part of the Crown Jewels of the United Kingdom, and is seen by millions of visitors to the Tower of London each year. The governments of India, Pakistan, Iran and Afghanistan have all tried to claim ownership of the Koh-i-Noor and demanded its return at various points in recent decades. However, the stone's early history is lost in the mists of time, and the British government insists the gem was obtained legally under the terms of the Last Treaty of Lahore.

Disappointment in the appearance of the stone was not uncommon. After consulting various mineralogists, including Sir David Brewster, it was decided by Prince Albert, the husband of Queen Victoria, with the consent of the government, to polish the Koh-i-Noor. One of the largest and most famous Dutch diamond merchants, Mozes Coster, was employed for the task. He sent to London one of his most experienced artisans, Levie Benjamin Voorzanger, and his assistants.

On 17 July 1852, the cutting began at the factory of Garrard & Co. in Haymarket, using a steam-powered mill built specially for the job by Maudslay, Sons and Field. Under the supervision of Prince Albert and the Duke of Wellington, and the technical direction of the queen's mineralogist, James Tennant, the cutting took 38 days. Albert had spent a total of £8,000 on the operation, which reduced the weight of the diamond by around 42 per cent, from 186 carats (37.2 g) to its current 105.6 carats (21.12 g).

The great loss of weight is to some extent accounted for by the fact that Voorzanger discovered several flaws, one especially big, that he found it necessary to cut away. Although Prince Albert was dissatisfied with such a huge reduction, most experts agreed that Voorzanger had made the right decision and carried out his job with impeccable skill.

When Queen Victoria showed the re-cut diamond to the young Duleep Singh, the Koh-i-Noor's last non-British owner, he was apparently unable to speak for several minutes afterwards.

After Queen Victoria's death, the Koh-i-Noor was set in the Crown of Queen Alexandra, the wife of Edward VII, that was used to crown her at their coronation in 1902. The diamond was transferred to Queen Mary's Crown in 1911 and finally to The Queen Mother's Crown in 1937. When The Queen Mother died in 2002, it was placed on top of her coffin for the lying-in-state and funeral.

All these crowns are on display in the Jewel House at the Tower of London with crystal replicas of the diamond set in the oldest crowns. The original bracelet given to Queen Victoria can also be seen there. A glass model of the Koh-i-Noor shows visitors how it looked when it was brought over to the United Kingdom in 1850. Replicas of the diamond in this and its re-cut forms can also be seen in the 'Vault' exhibit at the Natural History Museum in London.

During the Second World War, the Crown Jewels were moved from their home at the Tower of London to a secret location. In 1990, The Sunday Telegraph, citing a biography of the French army general, Jean de Lattre de Tassigny, by his widow, Simonne, reported that George VI hid the Koh-i-Noor at the bottom of a lake near Windsor Castle, about 32 km (20 miles) outside London, where it remained until after the war. The only people who knew of the hiding place were the king and his librarian, Sir Owen Morshead, who apparently revealed the secret to the general and his wife on their visit to England in 1949.

The Sancy, a pale yellow diamond of 55.23 carats (11.046 g), was once reputed to have belonged to the Mughals of antiquity, but is more likely of Indian origin owing to its cut, which is unusual by Western standards.

The shield-shaped stone comprises two back-to-back crowns (the typical upper half of a stone) but lacks any semblance to a pavilion (the lower portion of a stone, below the girdle or midsection).

The Sancy's known history began circa 1570. Several sources state it belonged to Charles the Bold, Duke of Burgundy. After the Charles died, in 1495 it passed to his cousin king Manuel I of Portugal.

When Portugal was threatened to become under the Spanish rule, claimant D. António António, Prior of Crato fled the country with the bulk of the Portuguese Crown Jewels. He spent then his life trying to get allies to regain the Portuguese throne in the French and English courts, and to have sold then the diamond to Nicolas de Harlay, seigneur de Sancy.

Other sources claim that the diamond was purchased in Constantinople by de Sancy. He was popular in the French Court and was later French Ambassador to Turkey. Something of a gem connoisseur, de Sancy used his knowledge to prosperous advantage.

Henry III of France
Henry III of France suffered from premature baldness and tried to conceal this fact by wearing a cap. As diamonds were becoming increasingly fashionable at the time, Henry arranged to borrow de Sancy's diamond to decorate his cap. Henry IV also borrowed the stone, for the more practical purpose of using it as security for financing an army. Legend has it that a messenger carrying the jewel never reached his destination, but de Sancy (by then Superintendent of Finance) was convinced that the man was loyal and had a search conducted until the site of the messenger's robbery and murder was found. When the body was disinterred, the jewel was found in the faithful man's stomach.

De Sancy later sold the diamond to James I (successor of Queen Elizabeth) about 1605 when it is thought the Sancy acquired its name. It was described in the Tower of London's 1605 Inventory of Jewels as "...one fayre dyamonde, cut in fawcetts, bought of Sauncy." James had it set into the Mirror of Great Britain.

The Sancy was briefly possessed by the unfortunate Charles I (King of England, Scotland and Ireland) and then by his third son James II. Beleaguered after a devastating defeat, James took shelter under Louis XIV of France, a fickle host who tired of his exiled guest. Facing destitution, James had no choice but to sell the Sancy to Cardinal Mazarin in 1657 for the reported sum of £25,000. The cardinal bequeathed the diamond to the king upon his death in 1661.

The Sancy was thus domiciled in France but disappeared during the French Revolution when brigands raided the Garde Meuble (Royal Treasury). As well as the Sancy, other treasures stolen were the Regent diamond, and the French Blue diamond which is known today as the Hope diamond.

The Sancy's history is unknown from then until 1828 when purchased by Prince Demidoff for £80,000. It remained in the Demidov family collection until 1865 when sold to Sir Jamsetjee Jeejeebhoy, an Indian prince, for £100,000. He sold it only a year later, creating another gap in its history. It reappeared in 1867, displayed at the Paris Exposition, carrying a price tag of one million francs; the gem then vanished again for forty years.

The Sancy next surfaced in 1906 when bought by William Waldorf Astor, 1st Viscount Astor. The prominent Astor family possessed it for 72 years until the 4th Viscount Astor sold it to the Louvre for $1 million in 1978. The Sancy now rests in the Apollo Gallery, sharing attention with the likes of the Regent and the Hortensia.

Weight : 55.23 carats (11.046 g)
Colour : Pale yellow, exact colour grade not recorded.
Cut : Shield-shaped modified brilliant cut
Country of origin : India
Discovered : Before 1570
Owner : The Louvre, Paris, France

Lesedi La Rona, formerly known as Karowe AK6, is the second-largest gem-quality diamond ever found, after the Cullinan. It is the third-largest diamond ever found after the Cullinan and the larger, non-gem black Sergio. It was found in the Karowe mine in Botswana on 16 November 2015. It weighs 1,111 carats (222.2 g; 7.84 oz) and is "nearly the size of a tennis ball".

The Lesedi La Rona is a colourless/white, type IIa diamond. It weighs 1,111 carats (222.2 g; 7.84 oz) and measures 65 mm × 56 mm × 40 mm (2.6 in × 2.2 in × 1.6 in). In size, it is second only to the Cullinan, discovered in 1905 in South Africa, which weighed 3,106.75 carats (621.350 g) .

The Lesedi La Rona was mined using Large Diamond Recovery ("LDR") XRT machines, and is the largest diamond recovered using machines for automated diamond sorting.

It was found on 16 November 2015, and the find was announced on 18 November. A day later, two more diamonds weighing 813 and 374 carats (162.6 and 74.8 g) were also found in the mine. Since the AK6 pipe was opened 18 months earlier, it has yielded over 1,000,000 carats (200 kg) of diamonds.

The diamond was first given a generic name after the mine (Karowe) and the pipe (AK6) where it was found. On 18 January 2016, Chief Executive Officer William Lamb of Lucara Diamond announced a competition, open to all Botswana citizens, to name the stone. In addition to naming the diamond the winner would receive P25,000 (about $2,170).

On 9 February 2016, Lucara Diamond announced that the stone had been named Lesedi La Rona which means "Our Light". The winner of the competition who named the diamond was Thembani Moitlhobogi from Mmadikola.

He stated that his reason for the name was that "the diamond is a pride, light and hope of Botswana". During the competition Lucara Diamond Corporation received 11,000 emails and 1,000 SMSs with name suggestions.

The exact value of the stone cannot be determined until it is decided how it will be cut and more details about its colour are known. Former diamond-mining geologist Phil Swinfen estimates, based on other similar sales, that the stone could be sold for $40–60 million.The process of selling and cutting the diamond "will likely take years to complete".