Diamond ring bought at car boot sale for $13 valued at $456,000

By Zamira Rahim, CNN
Updated 10:54 PM EDT, Mon May 22, 2017
This diamond, bought at a car boot sale for $13, is expected to sell for more than $400,000 at auction. It will hit the auction block at Sotheby's on June 7, 2017.
This diamond, bought at a car boot sale for $13, is expected to sell for more than $400,000 at auction. It will hit the auction block at Sotheby's on June 7, 2017.
Courtesy Sotheby's
The "Aurora Green" is the largest Fancy Vivid green diamond ever sold at auction. The stone went under the hammer on May 31, 2016 at Christie's auction house in Hong Kong, selling for $16,818,983.
The "Aurora Green" is the largest Fancy Vivid green diamond ever sold at auction. The stone went under the hammer on May 31, 2016 at Christie's auction house in Hong Kong, selling for $16,818,983.
courtesy christies
The world's largest blue diamond, an extremely rare gem known as "The Oppenheimer Blue", sold for $57.5 million at Christie's Geneva May 18, 2016, making it the most expensive diamond ever sold at auction.
The world's largest blue diamond, an extremely rare gem known as "The Oppenheimer Blue", sold for $57.5 million at Christie's Geneva May 18, 2016, making it the most expensive diamond ever sold at auction.
Christies Images Ltd 2016
The 14.62 carat Fancy Vivid stone is mounted on a platinum ring and flanked on either side by a trapeze-shaped diamond.
The 14.62 carat Fancy Vivid stone is mounted on a platinum ring and flanked on either side by a trapeze-shaped diamond.
Christies Images Ltd 2016
'The Unique Pink' is the largest Fancy Vivid pink pear-shaped diamond to ever be offered at auction.
'The Unique Pink' is the largest Fancy Vivid pink pear-shaped diamond to ever be offered at auction.
courtesy sotheby's
The diamond was sold for $31.6 million by Sotheby's, at an auction in Geneva. The price makes it the most expensive Fancy Vivid pink diamond to sell at auction.<br />
The diamond was sold for $31.6 million by Sotheby's, at an auction in Geneva. The price makes it the most expensive Fancy Vivid pink diamond to sell at auction.
courtesy sotheby's
Cubic zirconia replicas of the original and a modern cut of the Kohinoor diamond, one of the oldest and most famous diamonds in the world.<br />
Cubic zirconia replicas of the original and a modern cut of the Kohinoor diamond, one of the oldest and most famous diamonds in the world.
Bloomberg/Bloomberg/Bloomberg via Getty Images
The De Beers Millennium Jewel 4 has broken auction records in Asia.
The De Beers Millennium Jewel 4 has broken auction records in Asia.
CNN
The stone sold for $31.8 million, which makes it the most expensive piece of jewelry sold at an auction in Asia.
The stone sold for $31.8 million, which makes it the most expensive piece of jewelry sold at an auction in Asia.
courtesy sotheby's
Sotheby's <a href="http://edition.cnn.com/2016/03/20/entertainment/shirley-temple-ring-auction-sothebys/">auctioned</a> this 9.54 carat ring it says belonged to child star Shirley Temple on April 19, 2016. Though it was expected to fetch between $25 million and $35 million, it failed to sell.
Sotheby's auctioned this 9.54 carat ring it says belonged to child star Shirley Temple on April 19, 2016. Though it was expected to fetch between $25 million and $35 million, it failed to sell.
Sotheby's
This 12.03-carat blue diamond fetched $48.4 million at auction on November 11, 2015. It was previously the world's most expensive price-per-carat diamond sold.
This 12.03-carat blue diamond fetched $48.4 million at auction on November 11, 2015. It was previously the world's most expensive price-per-carat diamond sold.
FABRICE COFFRINI/Getty Images
The fancy, vivid blue diamond was discovered in South Africa in January last year.
The fancy, vivid blue diamond was discovered in South Africa in January last year.
FABRICE COFFRINI/Getty Images
In recent years, other high-value diamonds have hit the auction block. The 59.60-carat oval cut pink diamond known as "The Pink Star," went for $80 million at a 2013 Sotheby's auction. However, after the buyer defaulted on payment, it was returned to Sotheby's.
In recent years, other high-value diamonds have hit the auction block. The 59.60-carat oval cut pink diamond known as "The Pink Star," went for $80 million at a 2013 Sotheby's auction. However, after the buyer defaulted on payment, it was returned to Sotheby's.
EMMANUEL DUNAND/AFP/Getty Images
This 118.28 oval white diamond became the largest sold at auction when it went for $30.6 million at a Sotheby's auction in 2013.
This 118.28 oval white diamond became the largest sold at auction when it went for $30.6 million at a Sotheby's auction in 2013.
Peter Macdiarmid/Getty Images Europe/Getty Images
In April 2015, a 100-carat, emerald cut, D color, internally flawless diamond -- the largest of its clarity and cut to ever be shown at auction -- <a href="http://edition.cnn.com/2015/04/21/world/sothebys-flawless-diamond/">sold for $22 million.</a>
In April 2015, a 100-carat, emerald cut, D color, internally flawless diamond -- the largest of its clarity and cut to ever be shown at auction -- sold for $22 million.
Courtesy Sotheby's
The 76.02-carat 400-year-old Archduke Joseph diamond set a new record for price per carat for a colorless diamond in 2012, when it sold for $21.5 million at a Christie's auction.
The 76.02-carat 400-year-old Archduke Joseph diamond set a new record for price per carat for a colorless diamond in 2012, when it sold for $21.5 million at a Christie's auction.
FABRICE COFFRINI/AFP/Getty Images
In 2010, Hong Kong's largest jewelry retailer, Chow Tai Fook, bought <a href="http://edition.cnn.com/2015/09/03/luxury/gallery/11000-diamonds-wallace-chan/">one of the world's largest rough diamonds</a> for $35.3 million.
In 2010, Hong Kong's largest jewelry retailer, Chow Tai Fook, bought one of the world's largest rough diamonds for $35.3 million.
Courtesy Chow Tai Fook
Jeweler Wallace Chan and a team of craftsman worked 47,000 hours to transform the stone it <a href="http://edition.cnn.com/2015/09/03/luxury/gallery/11000-diamonds-wallace-chan/">into this piece</a>, which Chai Tai Fook estimates could be worth $200 million.
Jeweler Wallace Chan and a team of craftsman worked 47,000 hours to transform the stone it into this piece, which Chai Tai Fook estimates could be worth $200 million.
Courtesy Chow Tai Fook
A look at some of the world's most famous diamonds
CNN  — 

A 26-carat diamond ring, bought for $13 at a London car boot sale (an outdoor market where people sell personal possessions out of their cars) has been valued at up to $456,000. It is set to be sold on June 7 at a Sotheby’s auction.

The owner bought the ring in the 1980s, thinking it was a piece of ordinary costume jewelery.

“This is an extremely rare find,” said Jessica Wyndham, head of the auction house’s jewelery department. “We’re used to people coming in with pieces from their personal collections but this was exceptional.”

Rare delights: Where to see the world's most beautiful jewels

According to Wyndham, the diamond’s sparkle was likely hidden by the darkened ring mount and the old-fashioned style of the jewel’s cut.

“When we think of diamonds, we think of modern cuts, of brilliance,” Wyndham told CNN. “This wouldn’t have looked like that. The silver had tarnished and there was probably some dirt. These diamonds were made for candlelight, not our white artificial light, so it was all about trying to bring out its fire.”

The earliest known stone copy of the Ten Commandments sold at auction in Beverly Hills in 2016 for $850,000.
The earliest known stone copy of the Ten Commandments sold at auction in Beverly Hills in 2016 for $850,000.
Heritage Auctions
The stone was first uncovered in 1913.
The stone was first uncovered in 1913.
Heritage Auctions
"The tablet's significance is testament to the deep roots and enduring power of the Commandments that still form the basis of three of the world's great religions: Judaism, Christianity and Islam," says David Michaels, director of ancient coins for <a href="https://www.ha.com" target="_blank" target="_blank">Heritage Auctions</a>, who will be conducting the sale.
"The tablet's significance is testament to the deep roots and enduring power of the Commandments that still form the basis of three of the world's great religions: Judaism, Christianity and Islam," says David Michaels, director of ancient coins for Heritage Auctions, who will be conducting the sale.
Heritage Auctions
Specialists at Mossgreen auctions in Australia discovered this Ming dynasty banknote hidden inside the head of this 14th century Buddhist carving. The wooden sculpture represents the head of a Luohan -- an enlightened person who has reached Nirvana in Buddhist culture.
Specialists at Mossgreen auctions in Australia discovered this Ming dynasty banknote hidden inside the head of this 14th century Buddhist carving. The wooden sculpture represents the head of a Luohan -- an enlightened person who has reached Nirvana in Buddhist culture.
courtesy mossgreen auctions
Its face value was worth roughly $98 at the time of its circulation and the 700-year-old banknote is believed to have been handmade during China's Ming dynasty. Together, the banknote and sculpture are expected to fetch between $30,000 to $45,000 at auction.
Its face value was worth roughly $98 at the time of its circulation and the 700-year-old banknote is believed to have been handmade during China's Ming dynasty. Together, the banknote and sculpture are expected to fetch between $30,000 to $45,000 at auction.
courtesy mossgreen auctions
After studying the banknote and carving details, art specialists were able to estimate the sculpture's age, which dates back to China's Hongwu period in the 14th century.
After studying the banknote and carving details, art specialists were able to estimate the sculpture's age, which dates back to China's Hongwu period in the 14th century.
courtesy mossgreen auctions
Mossgreen specialists believe this is the first time a Ming dynasty banknote has been found inside a wooden Buddhist sculpture. They say it's more common to find relics and semi-precious stones left by monks inside Buddhist sculptures.
Mossgreen specialists believe this is the first time a Ming dynasty banknote has been found inside a wooden Buddhist sculpture. They say it's more common to find relics and semi-precious stones left by monks inside Buddhist sculptures.
courtesy mossgreen auctions
Ten ancient Roman and Ottoman coins were <a href="http://edition.cnn.com/2016/09/27/luxury/ancient-roman-coins-japan/">recently discovered in castle ruins in Okinawa, Japan</a>. This image shows the front of one of the Roman coins.
Ten ancient Roman and Ottoman coins were recently discovered in castle ruins in Okinawa, Japan. This image shows the front of one of the Roman coins.
Uruma Board of Education
"I couldn't believe they'd found coins from the Roman empire in Kasturen castle," archiologist Hiroyuki Miyagi, from Okinawa International University, told CNN. This is the front of one of the Ottoman coins.
"I couldn't believe they'd found coins from the Roman empire in Kasturen castle," archiologist Hiroyuki Miyagi, from Okinawa International University, told CNN. This is the front of one of the Ottoman coins.
Uruma City Educational Board
Archaeologists recently <a href="http://edition.cnn.com/2016/09/20/middleeast/jerusalem-nero-coin/index.html">unearthed</a> a rare 2,000 year old Roman coin during a <a href="http://edition.cnn.com/2016/09/20/middleeast/jerusalem-nero-coin/index.html">scientific dig</a> in Jerusalem. The gold coin features the face of Emperor Nero and was likely struck in 56-57 AD.
Archaeologists recently uneart