Where Do Diamonds Come From?

Table of Contents

They dazzle us with their shine and brightness. Their luster and transparency make them aesthetically pleasing. But they are very expensive. Have you guessed what I am talking about? Diamonds , of course! Diamonds are super hard and tough, and they don’t melt even when the temperature is too much to bear. Have you ever wondered why they happen to be so strong, and where exactly they come from?

A diamond in the making

If I told you that the pencil you hold in your hand every day is made of the same stuff that makes up diamonds, you would be surprised, right? Both diamonds and pencils are made of an element called carbon , a substance much cooler and more popular than simple pencils. What makes a diamond different from a pencil is the location of its formation.


To convert carbon into a diamond, extreme pressure and heat are needed. Such intense environmental conditions can only be found in the Earth’s mantle . The mantle is approximately 2900 km thick and lies just above the Earth’s super-heated core . Such heat might make us average Joes sweat and suffocate, but not carbon. The heat from the super-heated core of the Earth causes carbon atoms in the mantle to fuse with each other and form chemical bonds. And this is the reason a diamond is different from pencil lead. The chemical bonds formed as a result of these extreme conditions are different from the chemical bonds in a pencil lead, and make diamonds tougher and a much more precious commodity. A few lucky countries—Russia, Botswana, Australia, and Congo—have reported the presence of diamonds.

Earth’s layers
Pictorial depiction of the Earth’s layers, Credit: depositphotos.com/katerynakon

While some diamonds are built in just a couple of days, others may take millions or even billions of years to form (imagine the patience!). And when they do, volcanic eruptions bring such precious diamonds to the Earth’s surface. Volcanic eruptions are formed due to tectonic plate movements . A fancy term, but in simple words it refers to the movement of sections of the Earth’s inner layers toward, away from, or sideways against each other. To make things more interesting, while traveling to reach the Earth’s surface, diamonds may combine with trace elements such as nitrogen or boron to make colored diamonds. For instance, when the trace element nitrogen replaces some carbon atoms in the diamond’s structure, a rare yellow or orange diamond is formed.

Colored diamonds
Colored diamonds, Credit: depositphotos.com/tomisl.z

Fun Fact: A German scientist was able to convert peanut butter to diamonds. But if you are hoping to use your own jar to make a million dollars, you are in for a disappointment. Such artificially-made diamonds aren’t as desired and expensive as naturally occurring diamonds.

Twinkle twinkle, little diamonds in the sky?

The depths of the Earth may hold the sparkly wonders of the world. But locations in the vast, mysterious expanses of space aren’t too far behind! Scientists have discovered the existence of a rare form of a diamond called lonsdaleite in meteorites. It has been theorized that such space diamonds may have been formed as a result of a collision between an asteroid and a planet. While our usual Earth diamonds have a cubic structure, space diamonds have a hexagonal structure.

Let’s make some diamonds!

Waiting millions of years and placing our bets on volcanic eruptions to deliver us gleaming gems seems a bit exhausting. Hence, a process to make diamonds in the comfort of our laboratories has been discovered. The lab conditions mimic the conditions of the Earth’s heated mantle to make diamonds. Such diamonds aren’t structurally different from the ones made in the Earth’s mantle, but they are significantly less expensive. Imagine buying a historically important piece of artwork and a replica someone made of the painting. The replica will be much cheaper.





Diamond: a hard and expensive gem formed from carbon


Carbon / nitrogen: Chemical elements


Mantle: A section of the Earth’s interior


Core: The hot and dense center of the Earth; present below the mantle


Volcanic eruptions: Release of gases and lava


Tectonic plate movements: Movement of sections of Earth’s crust; causes earthquakes and volcanoes


Lonsdaleite: A form of diamond having origins in space


Asteroid: Small and rocky objects that orbit the Sun

Stachel, T., & Luth, R. W. (2015). Diamond formation — Where, when and how? Lithos, 220–223, 200–220. https://doi.org/10.1016/j.lithos.2015.01.028


Mantle. (n.d.). https://education.nationalgeographic.org/resource/mantle/


Vandenborre, L. (2021). Where do Diamonds come from? Beldiamond. https://www.beldiamond.com/blogs/guidance/where-do-diamonds-come-from


Sharp, W. E. (1974). A plate tectonic origin for diamond-bearing kimberlites. Earth and Planetary Science Letters, 21(4), 351–354. https://doi.org/10.1016/0012-821x(74)90173-3


Kraus, D., Ravasio, A., Gauthier, M., Gericke, D. O., Vorberger, J., Frydrych, S., Helfrich, J. P., Fletcher, L. B., Schaumann, G., Nagler, B., Barbrel, B., Bachmann, B., Gamboa, E. J., Göde, S., Granados, E., Gregori, G., Lee, H. J., Neumayer, P., Schumaker, W., . . . Roth, M. (2016). Nanosecond formation of diamond and lonsdaleite by shock compression of graphite. Nature Communications, 7(1). https://doi.org/10.1038/ncomms10970


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