There are approximately 200 naturally-occurring minerals in the world that we refer to as gemstones. Any rare gemstone comes in every color, quality, and quantity imaginable. But every so often, a jewel is discovered that distinguishes it from some of the most famous gemstones, entrancing us with its rarity, beauty, and one of many interesting art stories. Whether it's blue sapphire or black opal, all gemstones are breathtaking. The following one-of-a-kind gemstones and rare antique jewelry pieces discussed here are true legends. Whether owned by royalty, the social elite, or simply heralded as the very best of its kind ever discovered, let's delve into the fascinating realm of famous precious stones. 1. The Mackay Emerald The Mackay Emerald Weighing an unbelievable 167.97 carats, the Mackay Emerald is the largest cut emerald gemstone in the Smithsonian Museum National Gem Collection, making it one of the most famous gemstones in history. Mined in Muzo, Colombia, a locale acclaimed for its amazing emeralds, this gigantic green jewel was mounted by Cartier into a stunning diamond and platinum Art Deco necklace. In 1931, American financier Clarence Mackay acquired the emerald and diamond necklace and gave this precious gem as a wedding present to his new wife, Anna Case, a prima donna of the New York Metropolitan Opera. This emerald necklace highlights a famous gem that is truly spectacular in quality and color. Clarence Mackay with his wife Anna Case Mackay wearing the famous gemstone. According to accounts, Anna was invited to sing at a private party held at Mackay's home in 1916, two years after having divorced his first wife, Katherine Duer. Mackay instantly fell in love, but because of his personal beliefs, he would not propose marriage while Katherine was alive. Upon her passing in 1930, Mackay proposed to Anna, and the two wed the following year, at which time he gifted her this piece of emerald gemstone jewelry. The cabochon-cut precious stone presents the most perfect and desired green coloration for emeralds and is surrounded by 35 additional emeralds and 2,191 diamonds. When Anna died in 1984, she bequeathed this massive precious gemstone to the Smithsonian Institute, where it can be viewed in the Gem Hall of its National Museum of Natural History. View our current selection of untreated and rare emeralds. 2. The Sunrise Ruby The Sunrise Ruby Another precious gemstone, named after the poem by the 13th-century poet Rumi, is the Sunrise Ruby. Not only is it stunning, but it is also one of the most expensive colored gemstones that's not a famous diamond. Praised by the gem world's leading authorities, the 25.59-carat Sunrise Ruby ring is considered the rarest of all jewels. Originally estimated to be worth between $12 to $18 million dollars, this radiant-colored stone was sold in 2015 by Sotheby's Geneva in its Magnificent and Noble Jewels sale for $30.42 million dollars. The chairman of Sotheby's International Jewelry Division, David Bennett, stated that "during his 40 years in the industry, he has never before seen a ruby of this caliber." It has been evaluated by both Gübelin Gem Lab and the Swiss Gemological Institute, and both entities have praised the ruby's quality, finding the massive stone to be a natural, untreated Burmese ruby gemstone with perfect "pigeon blood" red coloration and incredible clarity and purity. Read our post about four interesting facts about rubies to learn more about “pigeon blood” coloration. This famous gem will go down in history as the greatest red gemstone. View our current selection of antique ruby jewelry. 3. The Logan Sapphire The Logan Sapphire Known as one of, if not the largest faceted sapphire in the world, is the incomparable Logan Sapphire. The jewel hails from Ceylon (present-day Sri Lanka), the world's prime location for exceptional sapphires, and weighs an astounding 422.99 carats. The mixed cushion-cut Ceylon jewel exhibits an incredibly rich, velvety blue coloration. It was examined and certified in 1997 by the Gemological Institute of America and found to be entirely natural and free of heat treatment, further stating in the report that the standing stone possesses "exceptional clarity" for a sapphire of its magnitude. It is believed the Logan Sapphire rock was acquired from a maharajah in India by Sir Ellice Victor Sassoon, 3rd Baronet of Bombay. At some point in time, it became the possession of American statesman and World War I veteran Colonel Meyer Robert Guggenheim of the prominent Guggenheim mining family. In the early 1950s, the Colonel gave the sapphire to his wife, Rebecca Pollard, as a Christmas gift. She kept the sapphire after Guggenheim died, and she remarried John A. Logan, from which the stone's name derives. In 1960, Mrs. Logan donated the sapphire to the Smithsonian Museum, where it can now be seen in the Gem Hall, along with the Mackay Emerald. View our current selection of antique sapphire jewelry. 4. The Aurora Australis Opal The Aurora Australis Opal Over 95% of the world's finest opals hail from Australia, with the Lightning Ridge region producing the most incredible black opals ever discovered. Named after the natural electrical phenomenon, the play of color in this striking gem evokes the ethereal Aurora Australis. This wonder of nature weighs a mesmerizing 180 carats, measuring 3-inches by 1.8-inches, and is believed to be the most valuable black opal in the world. Discovered in 1938 approximately six meters from the surface in the remains of what was once a seabed, the back of the opal actually bears the impression of a starfish! The extraordinary range of color, from deep reds and blues to intense greens and yellows, is second-to-none. Valued at $1 million dollars, the jewel was cut from a 12-ounce (1,860-carat) rough that, at the time, was not considered of any value. The rough was acquired by the renowned Australian opal firm Altmann & Cherny, who cut and polished the rare gemstone as it's seen today in the firm's Sydney showroom. Review our Guide to Opals to learn more about these precious stones. If you’re curious about opal jewelry, take a peek at our collection of opal jewelry. There may just be an antique opal ring calling your name. 5. The Black Prince's Ruby (Spinel) The Black Prince's Ruby is set within the British Imperial State Crown. The history of the royal gemstone can be traced back to its first known owner and namesake. England's Edward of Woodstock, better known as the "Black Prince," was given this 170-carat spinel in 1367 by the Moorish Prince of Granada in exchange for the English sovereign's military assistance in putting down a revolt. Some accounts say Edward demanded the ruby as payment, while others say it was willingly given to him. Regardless of how it was acquired, it has remained within the Royal Family since. Kings from Henry V through Richard III wore the royal gemstones in battle, as it was believed the ruby was a symbol of courage and vitality, protecting the wearer from evil and misfortune. Today, the Black Prince's Ruby royal gemstone holds a place of prominence within the Imperial State Crown of England, mounted directly above the Cullinan II diamond. Royals like Queen Elizabeth II have the pleasure of wearing many of these gemstone jewelry pieces. Are you interested in other areas of jewelry? Read and learn about Victorian jewelry history to expand your knowledge. Queen Elizabeth II wearing the Imperial State Crown. But what makes this gemstone's story even more fascinating is the fact that it's not actually a ruby...it's a spinel! So why is it still referred to as a ruby? Before modern technology, spinels and rubies were both known as “balas rubies” or simply rubies. It wasn't discovered until 1783 that the two gems, though they look incredibly similar, possess very different chemical properties: rubies being the red crystalline variety of aluminum oxide known as corundum, while red spinels are composed of oxygen, iron, magnesia, and chromium. Even after this realization, the ruby moniker just stuck, and continues to be referred to as a ruby to this day. Looking for stunning gemstone jewelry? Whether you prefer the brilliance of a blue sapphire or are searching for a stunning precious stone engagement ring, we are sure our collection has something for every gemstone collector. Browse our selection of antique opal rings.