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How To Make Your Own Diamonds

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uncut gems diamond crystals forming in rock close up

How Are Diamonds Formed?

Scientists are still figuring out just how diamonds were formed in the Earth roughly one-to-three billion years ago. But while the research continues, if you wanted to give creating diamonds a try, maybe because you’re ready to take the next step in your relationship or you're looking for an investment, here’s a rough recipe. 

First, it’s important to know that diamonds are made out of carbon. 

So, start by burying carbon dioxide about 100-150 miles deep in the Earth’s mantle. 

Then, you'll need to make sure that carbon is heated to about 2,200-degrees Fahrenheit. It’s very hot that deep in the Earth, so if luck has it, the conditions may be just right.

All of that overlying rock creates the high pressure. Which is needed for this next step. You'll need to squeeze the carbon under intense pressure: about 725,000 pounds per square inch. It’s the temperature and pressure that bond the carbon atoms to each other in a unique arrangement; one carbon atom to four other carbon atoms. That’s what makes a diamond so hard. 

How to retrieve the diamond

Then quickly send it upwards towards the Earth’s surface to cool. Scientists say a deep-seated volcanic eruption is what brings diamonds to the surface. The diamond needs to travel quickly to the surface to cool, (we’re talking hours) otherwise the would-be diamond would turn to graphite. Once the diamonds are brought to the surface and cooled quickly, the carbon atoms are locked in place and there’s not enough energy to turn them into graphite. 

Scientists believe the growth rates for diamonds depends a lot on the temperature and pressure, as well as on the presence of carbon, which is pretty rare in the Earth’s mantle. 

The time it takes to make a diamond should not be confused with the age of the diamond. Many diamonds that have been found are very old, dating back almost three billion years. But scientists say it’s likely the stone was formed and then sat around, waiting to be discovered. 

So best of luck in your diamond-making endeavors. And if the recipe doesn't quite work out, you can always opt for a diamond of the store-bought variety, for between an average of $3,000-$27,000 a pop (per carat).