Thursday, March 5, 2009

Centaurus 10 billion trillion trillion carats


Confirming what the Beatles always knew, astronomers have actually found a diamond in the sky - directly above Australia. It is the biggest known diamond in the universe, in fact. According to American astronomers at the Harvard-Smithsonian Centre for Astrophysics, a white dwarf star in the constellation of Centaurus, next to the Southern Cross, has been found to have a 3000-kilometre-wide core of crystallised carbon, or diamond. It weighs 2.27 thousand trillion trillion tonnes - that's 10 billion trillion trillion carats, or a 1 followed by 34 zeroes. The biggest earthly jewel is one of the British crown jewels, the 530-carat Star of Africa. However, this cosmic jewel is hidden beneath a layer of hydrogen and helium gases, with the diamond core making up between 50 and 90 per cent of its mass. "It's the mother of all diamonds," said astronomer Travis Metcalfe, who led the team of researchers that studied the star. "Some people refer to it as Lucy, in a tribute to the Beatles song Lucy in the Sky with Diamonds." Known officially as BPM 37093, the star confirms a theory, first raised in the early 1960s, that cool white dwarfs should have a diamond core. A white dwarf is what small stars, those up to about the size of the sun, turn into when they run out of nuclear fuel and die. The intense pressures at the heart of such dead stars compress the carbon into diamond. But confirming this theory has only been possible recently. Lucy "pulsates", which means its light fluctuates at regular intervals. "By measuring these pulsations, we were able to study the hidden interior of the white dwarf, just like seismograph measurements of earthquakes allow geologists to study the interior of the Earth," Dr Metcalfe said."We figured that the carbon interior of this white dwarf has solidified to form the galaxy's largest diamond." This means that other white dwarfs must also have diamond cores. Our own sun will become a white dwarf when it dies in 5 billion years. Two billion years after that, its ember core will crystallise as well, leaving a giant diamond in the centre of our solar system. Vince Ford, a research officer at Mount Stromlo Observatory near Canberra, said astronomers, including Australians, had observed the star for more than eight years. The star is about 50 light years away (500 trillion kilometres) - a fair distance as far as stars go. This means it is about 400 times too faint to see with the naked eye.

Friday, February 27, 2009

The Regent Diamond

The adventurous history of the Regent is very much like that of several other great diamonds. Greed, murder and remorse play a part in the opening chapter. Trouble - political, social, and personal - accompanies this gem to it's last resting place. Originally known as the Pitt, this 410-carat stone was one of the last large diamonds to be found in India. It is said to have been discovered by a slave in the Parteal Mines (also spelled 'Partial') on the Kistna River about 1701. The slave stole the enormous rough concealing it in bandages of a self-inflicted leg wound, and fled to the seacoast. There, he divulged his secret to an English sea captain, offering him half the value of the stone in return for safe passage to a free country. But during the voyage to Bombay, temptation overcame this seafaring man and he murdered the slave took th diamond. After selling it to an Indian diamond merchant named Jamchund for about $5000, the captain squandered the proceeds in dissipation and, in a fit of remorse and delirium tremens, hanged himself.

The Star of Africa

The Star of Africa, a pear shaped diamond weighing 530.20 carats, aka the Cullinan I. It measures 58.9 × 45.4 × 27.7 mm, and has 76 facets (counting the culet and the table). It is called the Cullinan I because it's the largest of the 9 large stones cut from the Cullinan Diamond, and the Cullinan II is the massive 317.40-carat cushion shaped diamond in the center-front of the Imperial State Crown of Great Britain. The Crown also features the Black Prince's Ruby, as well as St. Edward's Sapphire, and the Stuart Sapphire. All the stones in the crown seem to have a history. The Star of Africa holds the place of 2nd largest cut diamond in the world and is on display with the other Crown Jewels in the Tower of London.

The Lesotho Promise

Discovered at the Letseng Mine in Lesotho and tendered in Antwerp, the 603ct gem-quality rough stone has been on the cover of almost all magazines and newspapers worldwide. The world's 15th largest rough diamond ever to be discovered, has been transformed from its original state to 26 diamonds totaling 224 carats. At first, the Lesotho Promise was studied by engineers using most advanced scanning technology for 5 month.