10 of the World's Most Rare Gemstones

There are about 200 different types of natural gemstones discovered across the globe. In addition to the famous precious gems (diamonds, rubies, sapphires, and emeralds), there are countless semi-precious stones, some so exceptionally rare that their worth surpasses that of many top-tier jewels. Below are some of the most extraordinary gems from around the world.

1. Tanzanite

Tanzanite is a stunning blue variety of the mineral zoisite, exclusively found in a small region near Mount Kilimanjaro in Tanzania. Although it wasn't discovered in large quantities until the 1960s, its popularity has since soared, largely due to the marketing by Tiffany & Co. When heat-treated at high temperatures, tanzanite’s blue hue is enhanced, making most gems on the market heat-treated. However, tanzanite with a natural, intense blue color and no heat treatment is significantly more valuable. Since this gem is only found in one location and in limited supply, its value is expected to increase over time.

2. Black Opal

Opals are typically a creamy-white color, with their charm coming from the rainbow-hued inclusions that reflect light. Black opals are significantly rarer, with most of them found in the mines of the Lightning Ridge area in New South Wales, Australia. The darker the stone’s base color and the brighter the inclusions, the more valuable it becomes. One of the most prized black opals ever discovered is the Aurora Australis, uncovered in Lightning Ridge in 1938. Weighing 180 carats, this opal is particularly sought after for its large size and vivid harlequin pattern. In 2005, it was valued at AUS $1,000,000, which is approximately $763,000 U.S.

3. Larimar

Larimar is an extremely rare blue variety of the mineral pectolite, found only in a tiny region of the Dominican Republic. The turquoise stone’s name was coined by Miguel Méndez, who popularized the gem in 1974. He blended the first part of his daughter’s name, Larissa, with the Spanish word for sea, mar, to create the name larimar. While locals had known of the stone for generations, with small pieces washing up on the shore, it wasn’t until the 1970s that enough deposits were discovered in the earth to establish a mine.

4. Paraiba Tourmaline

Tourmalines are found in a range of colors across Brazil, but the Paraiba tourmalines stand out for their vibrant turquoise hue, which is due to their copper content. These exceptionally rare gems were first discovered in 1987 by the determined miner Heitor Dimas Barbosa, who had long believed something extraordinary lay beneath the hills of the Brazilian state of Paraiba. After years of unsuccessful attempts, he finally unearthed a neon-blue tourmaline that revolutionized the gemstone industry. The rarity of the stone (only one is found for every 10,000 diamonds) made it highly coveted. In 2003, similar turquoise-colored tourmalines were found in Nigeria and Mozambique, although some believe they are not as stunning as the Paraiba variety.

5. Grandidierite

Grandidierite was first identified in 1902 by the French mineralogist Alfred Lacroix, who discovered it in Madagascar and named it after the French explorer Alfred Grandidier, known for his expertise on the island's natural history. This exceptionally rare blue-green mineral has been found in several locations worldwide, but so far, only Madagascar and Sri Lanka have produced gem-quality specimens, and even those are incredibly scarce. Most of the known stones are translucent, but the rarest and most valuable examples are transparent. In fact, the first transparent grandidierite was initially mistaken for another rare gem, serendibite, as such stones had never been seen before. It was only after further analysis that it was correctly identified as grandidierite and was subsequently sold for an undisclosed price. It’s likely that any future discoveries of similarly high-quality stones would command an extraordinary price due to their extreme rarity.

6. Alexandrite

The fascinating color-changing gemstone alexandrite was first discovered in 1830 in the Ural Mountains of Russia and named in honor of Tsar Alexander II. A variety of chrysoberyl, this gem is especially prized for its color-shifting properties: In natural light, it appears blue-green, while under incandescent light, it turns red-purple. The extent of this color change varies from one stone to another, with some exhibiting only subtle shifts, but the most valuable stones are those that undergo a complete transformation in color.

While large specimens of alexandrite are rare (the Smithsonian houses the world’s largest known cut sample at 65.08 carats), most alexandrites are less than one carat. A stone of this size may be valued at around $15,000, but larger stones can command a price as high as $70,000 per carat.

7. Benitoite

Benitoite is found exclusively in a small region of California, near the San Benito River (which inspired its name). However, the mine ceased commercial operations in 2006, making this already rare gemstone even harder to find. Discovered in around 1907 by geologist George Louderback, benitoite is known for its striking deep-blue color and its fascinating ability to fluoresce under UV light. In 1985, it was designated the official state gemstone of California, recognizing that while trace amounts of the gem can be found in places like Arkansas, Japan, and Australia, California remains the only place where it can be mined in any significant quantity. Due to the difficulty of finding high-quality benitoite of substantial size, well-cut stones over two carats can command more than $10,000 per carat on the market.

8. Painite

Painite was discovered by British gemologist Arthur Charles Davy Pain in 1951 and officially recognized as a new mineral in 1957. For many years, only a single specimen of this dark red crystal existed, housed in the British Museum in London, making it the world’s rarest gemstone. Over time, more specimens were found, but by 2004, fewer than two dozen known painite gems were documented. However, in recent years, mines in Myanmar have started producing painite, and it is now said that over 1000 stones have been discovered. The extreme rarity of this gem has driven its value sky-high, with just one carat often selling for more than $60,000.

9. Red Beryl

Red beryl, also known as bixbite or red emerald, is so scarce that the Utah Geological Survey estimates that only one gem of this kind is found for every 150,000 gem-quality diamonds. Pure beryl is colorless and only takes on vibrant hues due to impurities in the rock: chromium and vanadium create the green color of emeralds, iron produces the blue or yellow tones seen in aquamarine and golden beryl, and manganese gives red beryl its deep crimson hue. Red beryl is found only in Utah, New Mexico, and Mexico, and most specimens are tiny, just a few millimeters long, making them too small to be cut for jewelry. The ones that are cut tend to be less than a carat, with stones of two or three carats being considered extraordinarily rare and valuable.

10. Taaffeite

In the 1940s, Austrian-Irish gemologist Edward Charles Richard Taaffe purchased a box of cut stones from a jeweler in Dublin, expecting them to be spinels. However, upon closer inspection, he noticed that one of the pale mauve stones didn't react to light the same way as the others. After sending it for analysis, it was confirmed that Taaffe had discovered a completely new gemstone, which was named 'taaffeite'. This was both a serendipitous and frustrating moment, as he had only found a cut gem and had no idea where the mineral naturally occurred.

Thankfully, after the discovery was made public, other collectors revisited their own spinel collections and several more taaffeite specimens were found. Eventually, the origin of the gemstone was traced to Sri Lanka, though a few have also been discovered in Tanzania and China. It is believed that fewer than 50 taaffeite stones exist, with most of them being housed in private or geological collections, making it so rare that the average person is unlikely to ever come across one.