Sparkling diamonds and verdant emeralds are some of the most sought-after and valuable gemstones in the world. But when it comes to rarity, which gemstone takes the crown? According to a 2019 review in the journal Minerals, emeralds are considered rarer than diamonds, with only 49 known deposits compared to approximately 1,000 rock formations containing diamonds. However, there are only 82 operational diamond mines globally, as stated in a 2022 article in the journal Reviews in Mineralogy and Geochemistry. The diamond industry is well-established, with international mining companies utilizing intricate pricing structures and commercial partnerships to meet the high demand for these precious stones.
In terms of production volume, diamonds also outshine emeralds. Natural Resources Canada reports that between 100 million to 150 million carats of diamonds are produced annually worldwide, equating to about 22 to 33 tons (20 to 30 metric tons). In contrast, only 7,000 to 9,000 kilograms of emeralds were produced in 2015 from major producing countries like Colombia, Zambia, Ethiopia, Madagascar, and Brazil, according to market research data compiled by Gemfields in 2022.
While the numbers may suggest that diamonds are more abundant, the geological processes involved in the formation of these gemstones tell a different story. Diamonds are formed deep within the Earth’s mantle, approximately 93 to 124 miles underground, making them the deepest-occurring gemstones on the planet. These precious stones originate as single crystals of carbon, created through specific changes in pressure, temperature, or chemical reactions within the mantle rock.
On the other hand, emeralds, which are the green variation of the mineral beryl, derive their color from chromium and/or vanadium impurities. The formation of emeralds is a more intricate process, requiring the convergence of beryllium-containing rocks with sedimentary environments rich in chromium and vanadium. This unique geological interplay often occurs in collisional zones, such as mountainous regions where tectonic plates collide, creating the ideal conditions for emerald formation.
Despite the higher production volumes of diamonds, the complex geological requirements for emerald formation render them rarer in terms of what is readily accessible to humans. Both gemstones necessitate specific geological circumstances to develop, but emeralds, with their intricate formation process, emerge as the more elusive and scarce of the two.
Hannah Loss, a reputable science journalist from Boston, delves into the rarity and value of gemstones, shedding light on the geological intricacies that contribute to their scarcity. With a background in environmental studies and a Master’s degree in journalism, Loss brings a unique perspective to the discussion of precious gemstones and their geological origins.
