De Beers Cullinan Blue = $57.5m

Sotheby’s Hong Kong auctioned the largest and most valuable blue diamond ever - the 15.1 carat, internally flawless, fancy vivid step-cut De Beers Cullinan Blue. The 39.35 carat rough stone was discovered by Petra Diamonds in South Africa’s Cullinan mine in April 2021. The diamond has a value “in excess of $45 million.” There have been only five blue diamonds over 10 carats ever to appear at auction, and, until now, none of them has topped 15 carats.

The most expensive blue diamond sold at auction previously was the 14.63 carat Oppenheimer Blue, sold at Christie’s Geneva in 2016 for £44 million.

Petra Diamonds (LON:PDL) 39.34 carat Type IIb gem recovered at its Cullinan mine in April was sold to De Beers and manufacturer Diacore for $40.2 million. Petra’s Blue Moon of Josephine diamond, cut from a 29.6-carat rough blue diamond, sold for $48.5 million in 2015. The price of $4 million per carat remains the world record. The Blue Moon of Josephine lost about 59% of its mass during cutting. If the same holds for the 39.34-carat blue diamond, the result would be a 16-plus-carat gem. At $4m per carat, the polished stone would be worth $64m. Diamonds get their natural blue color from small amounts of boron trapped in the crystal carbon structure during its formation.

Unusual High Jewel Brooches

Gianmaria Buccellati

Fuchsia Rose brings $6.7m

The Fuchsia Rose features a 8.82-carat purple-pink diamond at the center, flanked by two white diamonds of 6.1 carats. It was the leader at Christies, selling for $6.7 million, above it's high estimate. Once owned by a member of the Rockefeller family, a deep royal blue Burmese sapphire fetched $478k, far exceeding its high estimate of $150k.

Chaumet Fine Jewels

Marie-Étienne Nitot (1750-1809) settled in Paris in 1780 after having served his apprenticeship at Auber, then jeweller to Queen Marie-Antoinette. His aristocratic clientele remained loyal to him until the French Revolution in 1789.

He later became the official jeweller of Napoleon in 1802. Nitot created the jewellery that would offer the French Empire it's splendour and power. He designed and set Napoleon’s coronation crown, the hilt of his sword as well as many other pieces. François Regnault Nitot took over his father’s jewellery House on his death in 1809 and continued until the fall of the Empire in 1815. Napoleon’s exile caused Nitot to sell the business.

French Tiara given to Josephine by Napoleon.

Chaumet was bought in October 1999 by LVMH. After an unsuccessful attempt to penetrate the American market in the end of the 1990s, the company opened stores in Asia to fuel growth. Chaumet is now part of the watch and jewellery brands that includes TAG Heuer, Zenith, Fred, Hublot, Montres Christian Dior, and De Beers Diamond Jewellers.

Empress Joséphine Bonaparte's tiaras - $765k

Tiaras owned by Joséphine Bonaparte, the first wife of French Emperor Napoleon, went on sale after 150 years in private hands. Combined, they were expected to fetch up to £500,000 ($680k) at Sotheby'sNapoleon's lovelorn letters to Joséphine are renowned for their passion. She has been depicted as a clever seductress who ultimately relinquished her marriage when she and the emperor were unable to produce an heir.

Red Cross Diamond up for grabs

The Red Cross Diamond is part of Christies Magnificent Jewels sale next month in Geneva.

The 205.07 carat fancy yellow Red Cross Diamond was cut from a rough stone of 375 carats found in De Beers South African mine in 1901. The cushion-shaped diamond is one of the largest in the world and is famous for its pavilion, which is faceted in the shape of a Maltese cross. Estimate is $7.5m to $10.7m.

Royal Spinel - Balas Ruby

Spinel is the magnesium aluminium member of the spinel group. It has the formula MgAl2O4. Balas ruby is an old name for a red variety. After the 18th century the word ruby was only used for the red gem variety of corundum and the word spinel became used. "Balas" is derived from Balascia, the ancient name for Badakhshan. The Badakshan Province was for centuries the main source for red and pink spinels.

Spinel is most famous for its deep red variety that closely resembles ruby. The two gemstones can be very difficult to distinguish. Until the late 19th century, there was no distinction made between ruby and red spinel, as they look identical and are found in the same localities. Many famous old "rubies" were discovered to be spinel. Mining in Afghanistan has a history over 2,000 years as gold, silver and precious stones were routinely mined. Afghanistan's ruby/spinel mines were mentioned in the writings of many early travellers.

The Badakhshan mines were of great importance during the period from 1000–1900 AD. They were the source of many of the finest early red spinels in gem collections around the world, such as those in the crown jewels of Iran, the collection in Istanbul's Topkapi, Russia's Kremlin and Diamond Fund, and England's Tower of London.

Imperial State Crown

During the Soviet occupation, mining of all Afghan gem and mineral deposits was controlled by the state. However, since many mines lay in inaccessible areas, such mining became an important source of income for the rebels.

In the late 1980s, large reddish spinels were reported from the Pamir mountains of what is now Tajikistan. One 532 carat rough yielded cut gems of 146.43 and 27.81 carats. Ruby was also reported in eastern Tajikistan, near the border with China, in the early 1980s. Political difficulties and rugged terrain make Afghanistan a difficult country to explore, and Tajikistan is no better.

The Hope Diamond had a counterpart in the collection it was in — the Hope Spinel. Both belonged at one time to powerful London banker Henry Philip Hope, who died in 1839. The 45.52-carat Hope Diamond now resides in the National Museum of Natural History at the Smithsonian, while the 50.13-carat spinel headlined Bonhams’ Fine Jewelry sale in London on September 24, 2015. It was expected to fetch between £150,000 and £200,000. It made £962,500