Image: Courtesy Guernseys
This 887-carat raw emerald, one of the largest known rough emeralds from the Muzo mines, is probably the largest such emerald in the United States, according to Guernsey's. Marcial de Gomar believes the stone could yield a 400-carat polished gem, but the auction house says he would prefer that it be preserved, perhaps in a museum.
Image: Courtesy Guernseys
These teardrop-shaped Muzo emeralds carry a total weight of nearly 100 carats. Matching pairs of emeralds of this shape and size are extremely rare.
Image: Courtesy Guernseys
This museum-quality gem, called the "Marcial de Gomar Star," weighs nearly 26 carats and is one of the largest star emeralds ever found.
Image: Courtesy Guernseys
This sparkling diamond and Muzo emerald tiara converts into an elegant necklace.
Image: Courtesy Guernseys
Another view of the "Conquistadora," created by Manuel Marcial de Gomar from 889 brilliant diamonds and 35 Colombian emeralds.
Image: Courtesy Guernseys
This Marcial de Gomar-designed necklace features a 24.34 carat Muzo emerald salvaged from the Spanish shipwreck Nuestra Señora de Atocha. Baguette and round-cut diamonds and emeralds further enhance the central pendant, which bears the words "Plus Ultra," a reference to the Spanish history of conquest and the motto of the Colombian Marines.
Image: Courtesy Guernseys
Seven kite-cut Colombian emeralds and diamonds, set in platinum, form a cross.
Image: Courtesy Guernseys
These nine loose emeralds were among the treasure found on the Nuestra Señora de Atocha wreckage, and weigh between 2.5 and 26.72 carats each. The name refers to the Spanish Pillars of Hercules that appear on Spanish coins.
Image: Courtesy Guernseys
One of many gold coins salvaged from the wreck of the 17th-century ship, Nuestra Señora de Atocha, which sank off the coast of the Florida Keys. Coins and emeralds from this ship make up the most valuable treasures discovered from a shipwreck.
Image: Courtesy Guernseys
An extremely rare cabochon cat's eye emerald, the "Jaguar's Eye" exemplifies the deep, blue-green hues typical of Muzo emeralds. The stone's name, Guernsey's says, recalls a moment when a young Marcial de Gomar spotted a jaguar in the Colombia rainforest.
Image: Courtesy Guernseys
In creating this ring, Marcial de Gomar combined several rare cat's eye Muzo emeralds with diamonds and white gold.
Image: Courtesy Guernseys
The large (9.84-carat) cabochon emerald at the center of this necklace is surrounded by almost 13 carats of diamonds, with a further 60 diamonds strung along its chain. The design combines elements of Spanish and Native American art and contains 127 emeralds and 153 diamonds in total.
Image: Courtesy Guernseys
Beyond emeralds, Marcial de Gomar has also become entranced by conch pearls, an especially rare form of pearl. The "Alma Caribe," or "Soul of the Caribbean," weighing 22.5 carats, is one of the largest known such pearls.
Image: Courtesy Guernseys
This necklace combines two of Marcial de Gomar's passions: two large conch pearls and a trillion-cut emerald. The design was inspired by his wife, Inge.
CNN  — 

Cleopatra wore them. Elizabeth Taylor loved them. Egyptians believed they could bring eternal life. Though diamonds enjoy the reputation of being a girl’s best friend, emeralds in fact are more rare – and more valuable.

“Sought after for their rich color, regal history and identifiable look, emeralds are one of the most iconic gemstones in the jewelry industry,” Amanda Gizzi, a spokesperson for Jewelers of America, a New York-based trade association, said in an email.

On April 25, the public will have the opportunity to own some of the most magnificent and valuable emeralds in the world, when they go up for sale at Guernsey’s auction house in New York.

Image: Courtesy Guernseys
Nine pillars of the Andes

With more than 20 cut and raw stones and 13 spectacular pieces of jewelry, the rare emeralds on offer all come from a single collection that was compiled by emerald specialist Manuel Marcial de Gomar throughout his long career in the emerald industry.

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One of the highlights of the sale is a collection of cut emeralds from the great Spanish shipwreck Nuestra Señora de Atocha, a galleon that sank off the Florida coast in 1622. The wreck is considered “the most valuable known shipwreck in history,” according to the catalog accompanying the sale, largely thanks to its numerous Muzo emeralds, which are prized for their deep, clear green.

Sunken treasure

When treasure hunter Mel Fisher set out to retrieve the galleon’s lost bounty in the 1980s, he hired Marcial to help him appraise the stones and jewels salvaged from the ship’s wreckage.

Several of these stones, given to Marcial as payment for his work, are on offer in the Guernsey’s sale, and include the Nine Pillars of Andes, a group of nine rough stones totaling over 91 carats and carrying an estimated price of $2.5 million to $3.5 million; and the 4.39 carat Queen of the Sea, estimated to sell for $250,000 to $350,000.

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Also included in the sale is the 887-carat La Gloria, which Guernsey’s bills as “one of the largest museum-quality emeralds in the world,” (estimate $4-5 million); and the Marcial de Gomar Star Emerald, the largest star emerald ever found (estimate $2-3 million), notable for its double-sided cabochon, and one of only 11 star emeralds known to exist.

Image: Courtesy Guernseys
The Conquistadora as a necklace

Also included in the sale is the 887-carat La Gloria, which Guernsey’s bills as “one of the largest museum-quality emeralds in the world,” (estimate $4-5 million); and the Marcial de Gomar Star Emerald, the largest star emerald ever found (estimate $2-3 million), notable for its double-sided cabochon, and one of only 11 star emeralds known to exist.

Unique and untouched

Trends in jewelry that see a rising popularity in colored stones have also made emeralds especially desirable in recent years. In fact, Gizzi predicted 2017 “will be a big year” for colored stones, including emeralds.

Members of the beryl family of minerals, emeralds obtain their rich green color through chromium, vanadium or iron deposits in the mines. In the process, most stones form inclusions, tiny fractures or bubbles within their structure that can make them especially fragile.

Heritage Auctions
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.
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 Heritage Auctions, who will be conducting the sale.
courtesy mossgreen 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.
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.
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.
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.
Uruma Board of Education
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 City Educational Board
"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.
UNC Charlotte
Archaeologists recently unearthed a rare 2,000 year old Roman coin during a scientific dig in Jerusalem. The gold coin features the face of Emperor Nero and was likely struck in 56-57 AD.
Aileen Cynthia Amurao
In August 2016, the world's largest pearl was discovered under a bed in the Philippines, where it had lain forgotten for over ten years.
Courtesy de Grisogono
This 1,109 carat, tennis ball-sized diamond made headlines in November 2015 when it was pulled out of the Karowe Mine, in Botswana, by Canadian company Lucara Diamond Corp.
Clara Amit, Courtesy of the Israel Antiquities Authority
In May 2016, divers discovered a 1,600-year-old shipwreck while swimming the ancient Roman port of Caesarea. These rare bronze artifacts were recovered from the ship.
ATLAS
Over 1,300 pounds (590 kg) of bronze Roman coins dating to the 3rd century A.D. were unearthed in April 2016 by construction workers digging a trench in Spain.
Béla Polyvàs, Canton of Aargau
In January 2016, over 4,000 Roman coins were discovered by a fruit and vegetable farmer on a molehill in his cherry orchard in Switzerland.
courtesy william henry
The bead on this bracelet, from Portland-based design company William Henry, is actually made using fossilized mammoth tooth and dinosaur bones.

While the best emeralds, like the best diamonds, are “clear,” or inclusion-free, emerald connoisseurs generally also appreciate some inclusions, which they refer to as “jardins,” French for “gardens.” Nevertheless, because the general buyer does tend to prefer clear stones, many commercial jewelers treat their emeralds to make the jardins less visible.

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The gems of the Marcial de Gomar collection have not been subjected to such manipulations. The loose emeralds – some cut, others rough – represent some of the best natural stones to emerge from the world’s mines, according to Guernsey’s.

The making of a collection

Marcial’s collection reaches far beyond the stones themselves, however. In addition to several gold and silver coins, also salvaged from the Atocha wreck, the Guernsey’s sale features spectacular jewelry, designed by Marcial himself, such as the Corona de Muzo, which includes a 24.34-carat emerald from the wreck, combined with smaller emeralds and diamonds (estimate $5-6 million).

Or there is the extraordinary Conquistadora, crafted of 889 diamonds and 35 emeralds, which can be worn both as a necklace and as a tiara (estimate $150,000 to $250,000). That the auction is also being held online as well as in New York may seem odd to some: It is risky business, after all, to bid millions of dollars for a necklace or a raw gemstone you haven’t seen.

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However, Ettinger said, “Some bidders do indeed purchase very expensive objects without viewing them in person.” Alternatively, he added, “The emeralds are in our Manhattan vault, and can be seen any time between now and April 25.”