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Find Your Ring Size

Royal Coster
Diamonds Size
Internal Diameter / Circumference (mm)​
14,01
14,33
14,65
14,97
15,21
15,61
15,92
16,24
16,56
16,88
17,20
17,52
17,83
18,15
18,47
18,79
19,11

How To Measure

The Hands-on Method​ Measure an Existing Ring
  • 1. Grab a tape measure, length of string or strip of paper.
  • 2. 2. Wrap one of these objects around your finger. Mark the place where the two end of the measuring object come together.
  • 3. When using string or paper grab a ruler. Lay it on a flat surface and measure to where the marked point is.
  • 4. Use the chart presented above to acquire the correct ring size.
The golden Jubilee: How an ugly duckling became the biggest faceted diamond in the world - Royal Coster Diamonds

The golden Jubilee: How an ugly duckling became the biggest faceted diamond in the world

The cut of the Golden Jubilee

The ‘Unnamed Brown’, as the Golden Jubilee was first named, was considered something of an ugly duckling by most at first. Then De Beers gave it to Gabriel Tsiolkovsky. For the purpose of testing special tools and cutting methods that they developed for the intent to use on the flawless D-color Centenary. Gabriel Tolkovsky is a six-generation diamond cutter and the great-nephew of Marcel Tolkovsky who is the father of the modern round brilliant cut. Gabriel had already received a commission from De Beers to work on the 273.85 carats, Centenary Diamond. His techniques were in the avant-garde of the diamond cutting technology, and the Polish cutter would further polish them by devising experimental and ingenious tools.

Gabriel Tolkkovsky

The cutter was nothing short of daring. Because the yellow/brown diamond presented deep scars, cracks, and inclusions. Gabriel Tolkovsky tried to avoid fracturing the stone so as to not render it useless. To that purpose, he designed an underground room soundproof from the tiniest vibrations. For two years he toiled on the gem-quality stone. It wouldn’t be an overstatement to say the Golden Jubilee was born again in his hands. In 1988, the diamond had its first appearance in the world scene when De Beers company took it on tour as the champion stone to lead their centennial celebrations. After all, the Unnamed Brown wasn’t the ugly duckling anymore. It had matured into a 545.65-carat beauty, shining through a brilliant cushion cut and 148 facets. The color is now graded as ‘fancy yellow/brown'. When interrogated about it, Gabriel Tolkovsky called its technique ‘the fire rose cushion cut’. These tools and methods had never been tested before. The "Unnamed Brown" seemed the perfect guinea pig; it would be of no great loss should something go amiss. We can only assume the cutter knew how to tempt the diamond into revealing its many faces. Usually, a rose cut releases only up to 24 facets. With the stone’s shape resembling a rosebud with a flat bottom and a crown in the shape of a dome. However, the Golden Jubilee rose above anyone’s expectations. The golden jubilee diamond and its beautiful brown color source picture: Gem Select

How the Golden Jubilee became a royal diamond

To everyone's surprise, the result is a yellow-brown diamond in a fire rose cushion cut outweighing Cullinan by 15.37 carats. The stone is largely unknown to the outside world, as well as the Golden Jubilee's sister The Centenary. The Centenary was already selected and promoted to herald the Beer's centennial celebrations in 1988, yet in the end, the Golden Jubilee was given this honor. Displaying such brightness made the Golden Jubilee diamond worthy of royalty. While being toured around the world by De Beers, it caught the attention of Thai diamond-investors. So it goes that ten years after it had been unearthed the company sold the precious gem to a group led by Henry Ho of Thailand, head of the imposing Jewelry Trade Center in Bangkok. There was a mile-long queue to see the diamond, which outshone all other exhibits. The current whereabouts of the Centenary are unknown. The Golden Jubilee is known to have been purchased from De Beers by a group led by Henry Ho of Thailand in 1995. The diamond was brought to Pope John Paul II in the Vatican to receive the papal blessing. As a result, it was also blessed by the Supreme Buddhist Patriarch and the Supreme Imam in Thailand. Therefore, the Golden Jubilee Diamond was named by King Humboldt Adulyadej and given to him in honor of his 50th coronation anniversary. It was initially planned to mount the Golden Jubilee in the royal scepter. In the end Humboldt Adulyadej went for the second plan and had it mounted in a royal seal. Nowadays, the Golden Jubilee Diamond has an honorable seat among the Crown Jewels of the Royal Family of Thailand, always under heavy guard.

The worth of the Golden Jubilee

There is no actual price tag attached to the Golden Jubilee Diamond. However, there are estimations. The stone is valued at 4 to 12 million dollars. This price is based on the weight, cut, inclusions, and color of the diamond. If ever auctioned, it would probably score a much higher price because of its grand and turbulent history and fame. It is, after all, the Golden Jubilee, the one-of-a-kind Unnamed Brown. There is a very small chance it will ever be in an auction because the Thai royal family, like most royal families, is very protective of their crown jewels and they are seldom sold or put up for auction. If you would like to read more about famous diamonds you can check our blog top 5 most famous diamonds. And if you want to own an amazing diamond yourself look at our extensive collection.
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