Published on Jul 05, 2020
There are roughly 200 varieties of natural gemstone known in the world today. Alongside the world’s precious gems (diamond, ruby, sapphire, and emerald) are numerous semi-precious stones, some of which are so incredibly rare that their value outstrips many of the world's most valuable precious gems. A lot of them are sold and used in jewelry but at such impossible prices and in so small quantities that they are beyond the reach of the average customer. Some are rare because they’re simply found in one or two places in the world, others – because they are unreasonably difficult to mine.
Here are a few of the rarest from around the world.
1. Alexandrite: The amazing color-changing stone alexandrite was discovered in 1830 in the Ural Mountains in Russia and named after Russian 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 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.
2. Black Opals: While opals on the whole, are not rare, black opals are another story. Most black opals are only found in the mines in the Lightning Ridge area in New South Wales, Australia. Unlike standard opals that have a creamy white color, black opals have deep black or dark blue colors and bright flashes of color, making for a truly gorgeous look.
The darker the black colors of these opals, the more their inclusions stand out, and the more captivating the entire composition becomes. Black opals come with a hefty price tag but each stone is unique and truly special.
3. Red Beryl: Also called “Bixbite”, “Red Emerald”, and “Scarlet Emerald”, Red Beryl was not officially described until 1904. Chemically, it’s related to both Aquamarine and Emerald but it’s rarer than both. It’s only found in parts of Utah and New Mexico and is extremely difficult to mine in a sustainable economically fashion. Due to these mining difficulties, Red Beryl is so rare in jewelry that it’s estimated to be roughly 8,000 times rarer than the similar red rubies – themselves a very rare gemstone.
4. Kashmir Sapphires: Soft, velvety, saturated blue hues characterize Kashmir sapphires . These gems contain very fine inclusions of rutile that create this soft look. The mines that once produced them high in the Himalayas ran dry in the 1930s. As a result, the price of these extremely scarce stones rises ever higher. While few will ever have the privilege of owning one of these gems, museums have many pieces on display. They’re well worth a visit.
5. Taaffeite: Austrian-Irish gemologist Count 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—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 has 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 ordinary public is unlikely to ever encounter it.
6. Tanzanite: Found only in Tanzania, near the foot of Mount Kilimanjaro, this gorgeous gemstone is a blue variety of Zoisite. It was first discovered in commercial quantities in the 1960s and since then its popularity and value have soared thanks to jewelers such as Tiffany and Co. However, even though it’s quite popular and not as rare as some of the other gemstones on this list, Tanzanite is still only found in this one location in small quantities. Once that one Tanzanite mine is exhausted, primary Tanzanite sources will be depleted. Hence, this stone is called the ‘one-generation gemstone’ as the mines are expected to run out in this generation. Even so, Tanzanite continues to be less expensive than blue sapphire but can rival blue sapphire in its beauty.
7. Ammolite: Ammolite is an organic gemstone that’s only found in rather limited deposits in the Rocky Mountains in the U.S. It consists of aragonite shells of 65-million-year-old marine mollusks, the same material that creates pearls.
Ammolite is similar to coral or shell in that it originates from sea creatures but it’s different in that it’s fossilized shells that need to be dug up. You can see multiple incandescent colors on a single stone, sometimes every single color of the rainbow. It’s that unique property that makes it so highly valued in addition to its rarity – the more colors an Ammolite stone displays, the more expensive it is. [Click To Know: The Science of Gemstones ]