“Diamonds are formed from highly compressed coal.”

Many people have heard that diamonds are simply chunks of coal squeezed under immense pressure over time. This idea likely stems from the fact that both diamonds and coal are primarily composed of carbon, and the concept of intense geological forces transforming one material into another seems intuitively plausible. The imagery of coal mines and deep earth processes might also contribute to this misconception, leading to a convenient but incorrect narrative about how these precious gems come to be.

However, the scientific evidence clearly shows a different story for the vast majority of natural diamonds. Diamonds are actually formed much deeper within the Earth than coal deposits, typically in the mantle at depths of 90 to 125 miles. Here, under extreme temperatures (around 2,000 to 2,200 degrees Fahrenheit) and pressures (about 725,000 pounds per square inch), carbon atoms crystallize into the stable, incredibly hard structure of a diamond. Furthermore, most diamonds are billions of years old, significantly predating the formation of Earth's first land plants, which are the biological source material for coal.

The enduring belief in the coal-to-diamond myth is understandable. Both substances are valuable, carbon-based, and associated with being extracted from the Earth. The idea of a humble, black rock transforming into a sparkling gem is a compelling narrative. Yet, while both share a fundamental element, their distinct origins and formation processes highlight the incredible diversity of geological phenomena and the unique conditions required for nature's most dazzling creations.