4Cs of Diamond Quality by GIA

Often called black pearls, Tahitian cultured pearls can also be gray or brown in bodycolor with blue, green, purple or pink overtones. Some also show orient, a shimmer of iridescent rainbow colors on or just below a pearl’s surface. Want to learn more about pearls? Check out our Continuing Education seminar, The 7 Value Factors of Pearls, on May 19, 2021; 10 a.m.-12 p.m. PDT! This seminar will cover how to evaluate the quality of different types of cultured pearls, including akoya, South Sea, Tahitian and freshwater. Participants are encouraged to ask questions as they are guided along by GIA gemology instructors! Register now: https://bit.ly/3b2vCAA (Image 1) Photo: Matteo Colombo. Courtesy: Getty Images; (Image 2) Photo: SunChan. Courtesy: Getty Images

This (multi) million-dollar baby was bought by John D. Rockefeller, Jr., son of the famous oil tycoon, in 1934 from an Indian Maharajah rumored to have been the Nizam of Hyderabad. Rockefeller had it recut by Cartier in the 1940s and set for his wife, Abigail Aldrich. One of the most valuable sapphires in the world, it is remarkable for its size (62.02 carats) and clarity as well as its Burmese origin. Courtesy: Christie's

A pair of sweethearts. These diamond earrings feature a 0.73 carat Fancy blue heart-shaped diamond and a 0.63 carat Fancy Intense purplish pink heart-shaped diamond. Did you know that blue diamonds are colored by the element boron while pink diamonds are colored by distortions in their crystal lattice? Blue and pink diamonds are some of the rarest and most sought-after colored diamonds in the world. Know the quality of your colored diamonds with our suite of GIA Grading Reports: https://bit.ly/3ehDRuB Courtesy: Christie's

This spectacular 75.61 carat Colombian emerald (which had been a 107.67 carat rectangular emerald before it was recut in 1954) was part of Catherine the Great's collection of jewels. It was said that the Russian empress put on emeralds before tough meetings with generals; the tougher the meeting, the more emeralds she wore. Another female leader who used emeralds to impress and signal her wealth and power - Cleopatra, Queen of the Nile. The first known emerald mines were in Egypt, and Cleopatra was said to have draped herself in emeralds and gifted them to foreign dignitaries and diplomats. Photo: Russell Shor/GIA. Courtesy: Christie's

Madagascar is known for producing a variety of exquisite gems, including sapphire. One of its major deposits is Ilakaka, one of the world’s largest sapphire deposits. Here, local authorities have banned mechanical mining to give more people the opportunity to be employed in mining sapphire. The second image shows the rush site at Bemainty, near Ambatondrazaka, Madagascar where sapphires were discovered in 2016. (Image 1) Photo: Wimon Manorotkul. Courtesy: Neil Doohan. (Image 2) Photo: Rosey Perkins

The gift that keeps on giving. In 1955, Diamond Corporation, Limited then under the direction of Chairman Sir Ernest Oppenheimer donated more than 1,500 carats of diamonds to GIA. Named the Sir Oppenheimer Student Collection, this donation included a wide range of crystal shapes, sizes and quality, many of which were cut for educational purposes. This generous gift was given in recognition of GIA's contribution to the trade and allowed GIA to increase its diamond evaluation courses and supplement its grading training. Seen here from left to right are a 4.15 carat (ct) brownish octahedron with trigons, a 2.09 ct macle with trigons, a 1.34 ct colorless heart shape and a 3.06 ct cushion cut brown diamond. This collection will dazzle for many generations to come! Photo: Robert Weldon/GIA. Sir Oppenheimer Student Collection.

How was the Cave of Crystals in Chihuahua, Mexico, formed? Around 26 million years ago, magma pushed upward through the earth creating a limestone mountain near what is now the town of Naica. This forced hot, mineral-rich fluids into caverns and fissures, and it was from these waters that the giant crystals of Naica grew. Upon the cave's discovery in 2000, researchers from around the world including Leela Hutchison, GIA GG flocked to the cave to see its wonder firsthand, braving the cave's extreme heat and humidity. Since then, the mine providing access to the cave has flooded, preventing further exploration and leaving the magnificence of these crystals undisturbed. Learn more: https://bit.ly/3s6z4Qj Courtesy: Leela Hutchison

The 118.78 carat (ct) Graff Venus, a D-Flawless heart-shape diamond, was crafted from a 357 ct rough diamond crystal found at Letšeng, a mine jointly owned by the Kingdom of Lesotho and Gem Diamonds Ltd. At 10,000 feet (over 3,000 meters) above sea level, Letšeng is one of the highest-altitude diamond mines in the world. Temperatures can drop below zero degrees Fahrenheit during winter. Despite these challenges, mining there has proven worthwhile. Several large, high-quality diamonds have emerged from this mine, including the 910 ct Lesotho Legend, the 603 ct Lesotho Promise, the 550 ct Letšeng Star and the 493 ct Letšeng Legacy, among others. Diamonds from this mine yield the highest per carat value of any mine in the world! Image 2 shows scenery from the kingdom of Lesotho. (1) Courtesy: Graff; (2) Photo: Edwin Remsberg/Getty Images.

A delicious find. In September, 2020, 25-year-old Kettisak Kitphiar from Rayong Province, Thailand, found a 55.10-carat melo pearl in the meat of a melo species sea snail after cooking two shells that he purchased from a local market. Melo pearls are incredibly rare and desirable, in part because culturing them has never succeeded in the way it has with some commercially produced nacreous pearls. Most melo pearls fall into the yellowish orange to orange range and may be modif...ied by brown, but orange is the most sought-after color. Instead of an overtone or orient, they possess a fine porcelain-like surface, often exhibiting gleaming, flame-like patterns. This feature, combined with their distinctive color and often impressive size, makes them stand out in the pearl world. Melo pearls can form in any shape. Round, near-round and symmetrically oval or drop pearls are the most sought-after. The pearl that Kitphiar found is oval, which adds to its rarity. The right images in Image 1 show the pearl's flame-like structure, the bottom left shows the sea snails that Kettisak purchased for a little over US$5 each. Who knew that eating seafood could result in a once-in-a-lifetime find? Courtesy: Kettisak Kitphiar See more

Did you know that sapphire symbolizes truth, nobility and represents the heavens? Historically, it was favored by royalty and the clergy for these associations. This sapphire and diamond demi-parure dates back to 1870 and once belonged to Marie Bonaparte, a great-grandniece of Emperor Napoleon I of France. Its creator was Mellerio dits Meller, a French jewelry house founded in 1613 under the patronage of Marie de' Medici that claims to be the oldest family-run company in Europe. Clients of this house over the centuries have included Queen Marie Antoinette, Empress Josephine and others. Although the source of the sapphires in this necklace is not necessarily known, many sapphires used in royal jewelry during this time came from Sri Lanka. Courtesy: Sotheby's

A golden gift - in more ways than one. Angelina Jolie and jewelry designer Robert Procop donated this citrine necklace to the Smithsonian’s National Gem Collection in 2015. It features 64 cushion cut citrines and a stunning 177.11 carat pear-shaped citrine pendant set in 18K gold. Called the "Jolie Citrine Necklace," it is housed in the same hall that contains the Hope Diamond and the Star of Asia sapphire. Jolie designed this necklace in collaboration with Procop as part of the Style of Jolie collection. Proceeds from the sales of jewelry in this collection are donated to the Education Partnership for Children in Conflict, which builds schools for children in conflict-affected areas. The first few schools were built in Afghanistan. Courtesy: RP Studio

Despite Covid, these rockstars keep on shining. This 102.39 carat D-Flawless oval diamond fetched US$15.7 million at auction this October. One hundred-carat diamonds as a rule are exceedingly rare, said Quig Bruning, head of Sotheby’s jewelry department in New York. One hundred-carat D flawless are even more rare. This Type IIa diamond was cut from a 271-carat rough discovered in the Victor Mine in Ontario, Canada. Photo: ANGELA WEISS. Courtesy: AFP via Getty Images

Happy Halloween! Meet Greggory, a life-sized carving of a human skull, with a cranium and a separate mandible, crafted out of 25,189 carats of smoky quartz from Brazil! Smoky quartz is a brown to sometimes nearly black variety of quartz whose color is caused by radiation induced crystalline defects called color centers. It often exists in large sizes, which enables designers to get creative in carving sculptures out of them. Another creative use for smoky quartz - supposedly, the Chinese used to use panes of smoky quartz as sunglasses! Photo: Robert Weldon/GIA Collection

Dreams into reality. Fantasy cutting allows lapidary artists to let their imaginations run wild. As opposed to traditional faceting styles, fantasy cutting uses non-traditional design elements such as grooves, disks, and concave facets on the back of gemstones. Light is then reflected and refracted in stunning displays, as with this 64 carat amethyst from Bahia, Brazil, drawing the viewer into a fantasy realm. Learn more about gem carvings and fantasy cuts in the spring issue of G&G: https://bit.ly/3jPjsg0. Photo: Kevin Schumacher/GIA. Courtesy: Nick Alexander, Alexanders Jewelers.

Do you believe in curses? Besides its large size and intriguing color, one of the Black Orlov diamond's claims to fame is being cursed. The colorful story that has arisen around this gem is largely unsubstantiated, but it's a fascinating one nonetheless. According to legend, the 67.50 carat Black Orlov (originally 195 cts), also known as the Eye of Brahma, was discovered in the early 1800s in India, set as one of the eyes in a statue of the Hindu god Brahma in Pondicherry. It... was stolen and eventually made its way into the hands of a New York gem dealer and then two Russian princesses (the stone is said to be named after one of them). According to this tale, all three owners met grim ends. The curse was (supposedly) broken when a diamond dealer bought the gem and cut it into three smaller pieces, the present Black Orlov being the largest of them. Curses aside, natural-color black diamonds are extraordinary because they are colored by graphite, pyrite, or hematite inclusions that make them notoriously difficult to cut and facet. See more

We're falling for (and trippin' over) this gem. Nothing says fall like pumpkin spice lattes, cozy socks, apple cider and this orange fantasy cut imperial topaz. Did you know? During the 19th century, mines in Russia’s Ural Mountains were a leading source of topaz. The finest material was named imperial to honor the Russian czars and only the royal family could own it. Guess the Russian czars fell for it, too! Photo: Robert Weldon. Courtesy: Gems By Design, Inc. Kent, OH

Gems and jewelry are more than just beautiful. For millennia, they’ve been fraught with symbolism thought to contain medicinal powers and be able to ward off evil or bring their wearer joy and good fortune. Some jewels, on the other hand, are the opposite and are rumored to be cursed! Join our GIA Knowledge Sessions webinar tomorrow at 10 a.m. PDT as Senior Research Librarian Rose Tozer explores the beliefs and superstitions people have held about gems and jewelry throughout history. Learn about cursed gems, mourning jewelry, charms, amulets, jewelry symbols, such as the evil eye, and animal motifs, such as bats, scarabs, snakes, skulls, spiders and more! Register now: https://bit.ly/3oCqdoH

When these purple opals were sent to the GIA laboratory in Carlsbad, our scientists immediately suspected they had been dyed. Purple opal exists but it’s opaque and not known to display play-of-color like these specimens do. One of these opals was soaked in acetone and after 54 hours, the acetone turned light purple. After further testing, GIA scientists concluded these 'purple opals' are dyed hydrophane opals from Wollo, Ethiopia. Hydrophane opals are porous and readily absorb water. In fact, they sometimes feel sticky when held because they try to draw moisture from the skin. Their liquid-loving nature means their color can easily be changed with dye. Want to learn more about how GIA uncovered the truth about these opals? https://bit.ly/34DvtRn Photo: Robert Weldon/ GIA

Pumpkin spice and everything nice. Nothing says fall like pumpkins (or the Pumpkin Diamond). The 5.54-carat, Fancy Vivid orange Pumpkin Diamond was auctioned off on Halloween Eve in 1997 to Harry Winston, who purchased it for $1.3 million. Discovered in the Central African Republic (reportedly by a farmer), it was initially an unassuming, brown-looking rough. A diamond purveyor bought it on a leap of faith. In the hands of the right cutter, its stunning orange color was revealed! Photo: Shane McClure/ GIA

A sinister glow? The Hope diamond (R) and the Wittelsbach-Graff diamond (L) are two renowned blue diamonds that glow red under UV light. One of them - the Hope - is rumored to be cursed. The curse is said to have started when a thief stole the Hope from the brow of a temple idol in India. Since then, many of the diamond's owners, from King Louis XVI and Marie Antoinette to Evelyn Walsh McLean, have met tragic fates. The curse was said to have broken when Harry Winston donated... the gem to the Smithsonian Institution in 1958. Visitors can now see this magnificent and unusual diamond in person. Just don't get too close! The Wittelsbach-Graff diamond, said to be from the same mine in India as the Hope diamond, seems to have escaped this curse. Learn about famous diamonds that GIA has graded https://bit.ly/3mjFEAy. Courtesy: Smithsonian Institution (Hope Diamond) & Graff (Wittelsbach Diamond) See more

A mineral from the stars? One of the most popular diamond substitutes is lab-grown moissanite (silicon carbide). Moissainte was first discovered in nature by French chemist Henri Moissan in a crater in Canyon Diablo, Arizona in 1893 (although it had been grown in a lab two years before). This natural moissanite was likely brought from outer space by the asteroid that created the crater! At first, Moissan mistook the mineral for diamond, but in 1904, he correctly identified it... as silicon carbide. The mineral was eventually named "moissanite" after him. Moissanite is never found in large enough size or high enough clarity in nature for jewelry use. But high-quality lab-grown moissanites are produced in labs and are popular in both their colorless and colored forms. With incredible brilliance and fire and high hardness, it is closer to diamond in its physical properties than any other diamond substitute. Don't worry about not being able to tell lab-grown moissanite and diamond apart, though! One easy way to distinguish them is to look inside the gem. You will see a doubling of lab-grown moissanite's back facets (some people say this makes the inside of the stone look blurry), while diamond doesn't show doubling. The stunning bluish-green stone seen in this image is the 27.15 carat "Birth of the Star" lab-grown moissanite faceted by Victor Tuzlukov. What do you think? Is it a stellar gem? Photo: Robert Weldon. Courtesy: Victor Tuzlukov See more

A closer look at diamond impact. The Natural Diamond Council (NDC) is made up of 7 of the world's leading diamond companies. Together, they employ 77,000 people who earn 66% more than their national averages. At least $292 million of profits goes directly towards social programs such as education and healthcare. NDC members protect 1,023 miles of land, 3 times the amount of land used in mining, and recycle 83% of water used for diamond mining. The public desire for transparency is helping to make the impact of the diamond industry crystal clear. Photo: Lucian Coman. Courtesy: Lucara Diamonds

Now you see me... This 3.02 carat beauty is a contra luz opal from Ethiopia. The play-of-color of this shy gem only manifests itself under transmitted light. In fact, contra luz means "against the light" in Spanish. While it might not display its full magnificence under most lighting situations, under transmitted light, contra luz opal is truly a delight! Courtesy: Uniquegems from OpalAuctions.com

Gemstone royalty. The Raj Pink at 37.30 carats is the world's largest known Fancy Intense Pink diamond. Found in South Africa in 2015, it was described by GIA graders as an astonishing stone with a bright and ravishing fancy intense pink color. Less than .02% of the diamonds that move through GIA's labs each year are predominantly pink. (Image 1) Photo: Tristan Fewings/Getty Images for Sotheby's. (Image 2) Courtesy: Sotheby's