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There are roughly 200 varieties of natural gemstones known in the world today. Alongside precious gems (diamonds, rubies, sapphires, and emeralds) are numerous semi-precious stones, some of which are so uncommon that their value outstrips many of the world’s priciest jewels. Here are a few of the rarest from around the world.

Tanzanite is a beautiful blue variety of the mineral zoisite and found only in a small area near the foot of Mount Kilimanjaro in Tanzania. The stone was not discovered in commercial quantities until the 1960s, and since then its popularity has grown tremendously, thanks largely to the efforts of Tiffany & Co. Heat-treating tanzanite at very high temperatures can improve the blue coloration, so most gems on the market have been treated in this way—but any tanzanite that has not been heat-treated and has a strong blue color naturally will be of a much higher value. Because it is only found in one location in a finite quantity, the value of tanzanite will likely soar over time.

Opals are usually a creamy-white color and are made special by the rainbow-colored inclusions that reflect light. Black opals are much rarer because almost all of them are found in mines in the Lightning Ridge area of New South Wales in Australia. The darker their background color and brighter the inclusions, the more valuable the stone. One of the most valuable black opals of all time is the Aurora Australis, which was uncovered in Lightning Ridge in 1938. The 180-carat opal is especially admired due to its large size and intense harlequin coloration. In 2005 it was valued at AUS $1,000,000, or about $763,000 U.S.

Larimar is a very rare blue variety of the mineral pectolite and is found in only one small area of the Dominican Republic. This turquoise stone’s name was created by Miguel Méndez, who brought the stone to prominence in 1974—he took the first part of his daughter’s name, Larissa, and combined it with the Spanish word for sea, mar, to create the portmanteau larimar. Locals had known of the existence of the stone for generations, because small examples had washed up on the seashore, but it was not until the 1970s that sufficient quantities were found in the ground to open a mine.

Tourmalines are common in many colors across Brazil, but the Paraiba tourmalines are the only stones with a bright turquoise hue, thanks to their copper content. The very rare gems were discovered in 1987 by determined miner Heitor Dimas Barbosa, who had been driven by a belief that something special lurked under the hills of the Brazilian state of Paraiba. After years of fruitless digging, he finally unearthed a tourmaline of unrivaled neon blue that set the gem market alight. The extremely rare stone (only one is mined for every 10,000 diamonds) then became intensely sought-after. In 2003 very similar turquoise-colored tourmalines were found at mines in the mountains of Nigeria and Mozambique, although some say they are not quite as striking as the Paraiba tourmaline.

Grandidierite was first described in 1902 by French mineralogist Alfred Lacroix, who found it in Madagascar and named it in honor of the French explorer Alfred Grandidier, an expert on the island’s natural history. This extremely rare blue-green mineral has been found in a number of places around the world, but so far only Madagascar and Sri Lanka have produced any gem-quality stones, and they are still extremely scarce. The majority of the known stones are translucent, but the most rare (and therefore most valuable) example ever found was transparent. In fact, the stone was initially assumed to be another rare gem, serendibite, because grandidierite of that color and transparency had yet to be seen. The gem was only identified as grandidierite after expert analysis and was subsequently sold for an undisclosed sum. It’s safe to assume that if a gem of similar quality were to be unearthed, its scarcity alone would ensure it fetched an extremely high price.

The amazing color-changing stone alexandrite was discovered in 1830 in the Ural Mountains in Russia and named after Tsar Alexander II. A variety of chrysoberyl, the stone’s remarkable color-shifting capability makes it especially sought-after: In sunlight the stone looks blue-green, but under incandescent light it becomes red-purple. The degree of color change varies from stone to stone, with some only showing marginal change, but the most valuable are clear stones that demonstrate complete color change.

Although some large examples of the stone have been found (the Smithsonian houses the world’s largest known cut sample of alexandrite at 65.08 carats), the majority are under one carat. This means that the value of a gem under a carat may only be $15,000, but a stone larger than one carat might fetch as much as $70,000 per carat.

Benitoite is mined only in one small area of California near the San Benito River (hence the name), but the mine closed for commercial mining in 2006, making this gemstone even more scarce. The gem was first identified around 1907 by geologist George Louderback and has a deep-blue color that shows especially interesting qualities when caught under UV light, when it fluoresces. The gem was named the official state gemstone of California in 1985 in recognition of the fact that, despite it being found in trace quantities in Arkansas as well as Japan and Australia, California is the only place where it can feasibly be mined. Due to the rarity of discovering a good quality benitoite of a reasonable size, it can fetch huge prices on the open market—a well-cut benitoite stone at over two carats can fetch more than $10,000 a carat.

Painite was discovered by British gemologist Arthur Charles Davy Pain in 1951 and recognized as a new mineral in 1957. For many years only one specimen of the dark red crystal was in existence, housed at the British Museum in London, making it the world’s rarest gemstone. Later on other specimens were discovered, although by 2004 there were still fewer than two dozen known painite gems. However, in recent years a couple of mines in Myanmar have begun to produce some painite, and there are now said to be over 1000 stones known. The scarcity of this gem has made it extremely valuable and just one carat can fetch more than $60,000.

Red beryl, also known as bixbite or red emerald, is so rare that the Utah Geological Survey estimates a single such gem is uncovered for every 150,000 gem-quality diamonds. Pure beryl is colorless and only gains its bright hues from impurities in the rock: chromium and vanadium give beryl a green color resulting in an emerald; iron provides a blue or yellow tint creating aquamarine and golden beryl; and manganese adds the deep-red color to create red beryl. Red beryl is only found in Utah, New Mexico, and Mexico, and the majority of examples found are just a few millimeters in length, too small to be cut and faceted for use. Those that have been cut are generally less than a carat in weight, and a red beryl of two or three carats would be considered exceptional.

Austrian-Irish gemologist Edward Charles Richard Taaffe bought a box of cut stones from a jeweler in Dublin in the 1940s, thinking he had purchased a collection of spinels. But on closer inspection, he noted that one of the pale mauve gems was not reacting to the light in the same way as the rest of the spinels, so he sent it off to be analyzed. The results revealed that he had discovered a hitherto unknown gemstone—dubbed “taaffeite”—which was a serendipitous but frustrating situation, since he had discovered a cut gem and had no idea where the mineral naturally occurred.

Fortunately, once the new stone had been announced, many other collectors re-examined their own spinel collections and a number of other samples were uncovered. Finally, the source of the stone was tracked down to Sri Lanka, although a handful have also been found in Tanzania and China. It is thought that less than 50 examples of taaffeite exist—many of which are housed in geological and private collections, making this gemstone so rare the general public is unlikely to ever encounter it.

A version of this story was published in 2016; it has been updated for 2023.

When hikers in the Ötztal Alps stumbled on a body melting out of a glacier in September 1991, they thought they had found an unfortunate mountaineer who had disappeared perhaps a couple decades prior. But as soon as it was revealed that the mummified remains dated back 5300 years—and that the man had been murdered by an arrow to the back—researchers knew they had to solve the most fascinating ancient forensic case ever found. Nicknamed Ötzi, the Iceman, and Frozen Fritz, the body of a man who was around 40 or 50 years old when he died in the Copper Age continues to generate new data about a past era and shows links to contemporary people. Here are 13 surprising facts about Ötzi.

Ötzi might very well be the oldest person ever subject to a custody dispute. He was discovered in a part of the Alps mountain range that is right on the border between Austria and Italy. Complicating the find is the fact that the glacier in which he was entombed for millennia has shrunk since the official country border was established in 1919. This means that, although the find site of the mummy drains into Austria, the place Ötzi was actually resting is about 100 meters into Italian territory. Originally, Ötzi was studied at Innsbruck University in Austria, but since 1998 he has been displayed and studied at the South Tyrol Museum of Archaeology in Bolzano, Italy.

In 1991, an upright, carved stone was found in the town of Laces, near the Ötztal Alps where the Iceman was discovered. Although the stone was reused in modern times for the altar of a church, it dates to the Copper Age, just like Ötzi. One of the carvings on it depicts an archer shooting an arrow into the back of an unarmed man—which bears striking similarities to how scientists know Ötzi died. This circumstantial evidence, though, has not convinced most researchers.

Even though Ötzi was comparatively old when he died, he was not exactly healthy. Whipworm parasite eggs were found in his gut contents, so he probably suffered from nausea, vomiting, and diarrhea. His body also produced a full genome of H. pylori, a common stomach bug responsible for ulcers and other tummy troubles. There is also evidence that he had ingested a medicinal herb called hop hornbeam shortly before his death, possibly to help his indigestion. And one fingernail was found to have Beau’s lines, which can be created when the immune system is compromised. Ötzi’s fingernail shows he was ill several times in the four months prior to death.

Since Ötzi died while going about his daily life, the artifacts found with him give us a snapshot in time. Two particularly curious objects were spheres of botanical material about the size of walnuts that were strung on leather straps. Analysis of the masses indicated they were a fungus called Piptoporus betulinus. Notably, this fungus—if eaten—both causes diarrhea and can protect against certain mycobacteria. It is likely that Ötzi was ingesting this fungus in an attempt to treat his whipworm—the diarrheal action would have helped him get rid of the parasite’s eggs, while the antibiotic properties of the fungus would have killed off other intestinal bugs. Fungi like this were used for medicinal purposes until the 20th century.

The mummy boasts 61 different tattoos, and they are the oldest physical evidence of tattooing in the world. While the Iceman doesn’t have “MOM” on his biceps or a butterfly on his lower back, his tattoos are still quite interesting. They were made by scratching his skin and rubbing charcoal in the fresh wound, resulting in groups of lines or crosses. It has also been suggested that their placement over joints may have been an attempt to treat pain. As the oldest tattooed person ever found, Ötzi holds a Guinness World Record.

Long before Dolce & Gabbana dressed dapper Italian men, Ötzi was mixing materials to create his clothing. A 2016 study revealed the variety of species used to make Ötzi’s outfit. He wore a sheepskin loincloth, goat hide leggings and coat, and a hat made of the skin of a brown bear. Even his accessories were diverse: His shoelaces came from wild cows and his quiver from roe deer.

Ötzi’s field kit held a surprising number of different tools. There was a copper-bladed axe, which marks him as high status; a flint dagger and its tree-fiber sheath; and a bow made out of a yew tree. His quiver, fashioned out of deer hide with hazel wood supports, contained two finished arrows and a dozen unfinished shafts. He had a net for catching rabbits and birds, as well as a marble disc with a hole in the middle for hanging or carrying dead fowls. He also carried cylindrical containers made of birch bark, which kept charcoal embers hot for hours so he could quickly make a fire. His teeth were worn particularly on the left side, meaning he may have used his mouth to help work leather. The Iceman’s hair also revealed high levels of arsenic, suggesting he was a pro at smelting ores to make copper.

Ötzi was short and stocky, around 5 feet 2 inches tall and 135 pounds, with strong legs. Visible injuries suggest he engaged in combat: Several right-sided rib fractures had healed, while Ötzi was struck in the head shortly before his death. A protein analysis of his brain reveals some healing, particularly in the form of blood clots—but those could have caused a stroke or embolism. The Iceman also suffered a long, deep stab wound to his right hand. Based on the stage of healing evident from the wound tissue, it occurred three to eight days before his death. And of course, the arrow lodged in his left shoulder was likely the ultimate cause of death. In short, Ötzi was a hunter and a fighter.

The materials in the Iceman’s stomach revealed both his last meal and the meal before that. A 2018 study published in Current Biology tested Ötzi’s stomach contents and found traces of his final meal: dried ibex meat and fat, red deer meat, einkorn wheat, and remnants of a toxic plant. In the early 2000s, scientists conducted a DNA analysis of samples of digested food collected from his colon. Ötzi’s second-to-last meal consisted of ibex meat along with various species of cereals and dicots (a group of flowering plants). The discovery of red deer in his digestive system is especially interesting, since depictions of that animal figure prominently in archaeological finds throughout the Alps in this time period.

Between Ötzi’s top two teeth is a natural diastema, which is the anatomical term for a gap in the teeth. Among modern adults, about 10–20 percent have this gap. Researchers also saw in the Iceman’s mouth third molar agenesis—the anatomical term for lacking wisdom teeth. Around 35 percent of people today lack wisdom teeth. Ötzi was also missing some bones—the smallest of the ribs on either side. This lack of ribs is not unheard of, but it only affects about 5 percent of the population.

The Iceman’s genome was sequenced in 2012, revealing he had brown eyes and O-type blood, was lactose intolerant, and likely had Lyme disease. The mutations in Ötzi’s paternal genetic line are most commonly found in Sardinia and Corsica today, meaning those areas likely have descendants of his genetic family. Another study in 2013 tested thousands of modern men in the Alps and discovered that 19 men in the sample shared a genetic lineage with the Iceman. His maternal DNA line, however, appears to be extinct. So if you’re a guy and your ancestors go back to this roughly 620-mile band between Sardinia and the Alps, there’s a chance you could be related to Ötzi.

We all know that every ancient mummy is cursed, so of course the Iceman has his own story. In 2005, rumors circulated that the deaths of at least five people may have been related to a mummy’s curse. Helmut Simon, one of the two hikers who discovered the Iceman, died falling off the side of a mountain. An Alpine guide who airlifted the mummy out of the glacier died in an avalanche. A journalist who filmed the recovery of the mummy died of a brain tumor. A forensic expert who touched Ötzi with his bare hands died in a car accident en route to a conference to talk about the mummy. Even the death of the head of the research team at Innsbruck University has been attributed to Ötzi’s curse, in spite of the fact it was from multiple sclerosis. There is, of course, no evidence that these deaths are related to anything other than bad luck or coincidence.

Ötzi has been thoroughly CT scanned over the years for analysis. In 2016, CT scans were meshed with digital photographs, 3D printed, and then painted to create three life-size Ötzi clones. The Iceman’s first two 3D prints are on display at the DNA Learning Center at Cold Spring Harbor Laboratory, in Cold Spring Harbor, New York, along with 3D printed bones from his body. The third life-size print remains at the South Tyrol Museum of Archaeology, along with the real migratory hunter-herder, whose own journey has lasted more than 50 centuries.

A version of this story ran in 2016; it has been updated for 2023.