Geologists have sifted through over 5,000 minerals known to date and identified a handful of the world’s rarest minerals, many times rarer than diamonds. These minerals were created in extreme instances where you had to have the perfect ratio and amount of elements in specific speciations, ideal temperature and pressure and let’s not forget time. The combination of these factors produce some out of this world minerals, many of which are more rare than the most expensive gemstones in the world.
Some of the world’s rarest minerals are so small in quantity. The world supply could fit on a quarter, with the whole world’s supply being smaller than the world’s largest uncut diamond. The key defining feature to categorize an extremely rare mineral is that it is found in five or fewer sites around the globe, with many of the minerals on the list only being found in one known location on Earth.
Due to the extreme environment many of these minerals were formed, some will melt at normal atmospheric conditions, evaporate entirely or decompose in sunlight. However, the clues these minerals provide scientists are indicative of extreme conditions found within the Earth’s crust. In addition, clues as to the biological history of the Earth is linked to many of these rare minerals.
Dr. Robert Hazen from the Carnegie Institute recently published a paper in American Mineralogist outlining the nature and significance of the world’s rarest minerals. Hazen identified four key criteria that describe rare minerals.
- Specific and extreme temperature and pressure, often with limited ranges during mineralization.
- Presence of extremely rare elements that are not often found on Earth’s surface or outer crust.
- The presence of unusual ambient conditions, where the mineral would rapidly break down under normal ambient conditions.
- Sample bias that comes about when there is a lack of crystal faces to detect, microscopic minerals that go unnoticed, locations that are under sampled and hard to get to, etc.
Dr. Hazen points out that many of the gems portrayed as rare are in fact not considered mineralogically rare, often times found abundantly in many places around the world.
“However, diamond, ruby, emerald, and other precious gems are found at numerous localities and are sold in commercial quantities, and thus are not rare in the sense used in this contribution. Uses of the word “rare” in the context of “rare earth elements” or “rare metals” are similarly misleading, as many thousands of tons of these commodities are produced annually.”Of the total 5,090 minerals cataloged, less than 100 of those minerals make up approximately 99% of the Earth’s crust, and just a few speciations of Feldspar make up about 60%. The subset of extremely rare minerals is often intertwined with biological processes or a result of biogeochemistry.
One of the rarest minerals in the world is Fingerite, only known to exist near the summit of the Izalco Volcano in El Salvador. This extremely rare mineral is a specific combination of vanadium and copper that require a very narrow range of environmental conditions to form. On top of that, it’s so unstable that every time it rains, Fingertie washes away.
Published in the journal American Mineralogist.