If you like the idea of staying glitzy long after your death, it’s possible to turn your Earthly remains into a sparkling diamond.
Diamonds are made of pure carbon that has been arranged in a crystal. Most were formed between 1 and 3 billion years ago, deep below the Earth's surface under intense heat and high pressure. Being raised in these extreme conditions endows the diamond with a strongly bonded atomic structure, making them the toughest substance in the world (or at least one of them).
It is also possible to “grow” diamonds in a lab using a machine that mimics the natural processes that create diamonds found in the Earth. First developed in the 1950s, this technique is known as the High Pressure High Temperature (HPHT) treatment. It typically involves heating the carbon source materials to over 2,300°C (4,172°F) and subjecting them to pressures of 6.5 to 8.5 GPa (that’s roughly the equivalent of balancing a commercial jet plane on a finger).
Along with a small diamond “seed” that acts as a formation site and a catalyst, the main ingredient you need is carbon – an element that humans have plenty of. Around 18.5 percent of human body mass is made up of carbon and our cremated remains usually yield between 2.5 to 8.5 milligrams of carbon. Since you only need 1 milligram of carbon to make an artificial diamond, this is more than enough material to work with.
The carbon in cremated bones exists in the form of carbonate, a salt consisting of one carbon and three oxygen atoms. First, gasses are used to separate some of the impurities in the carbonates, then carbonate is turned into pure carbon using extremely high temperatures and a low-oxygen environment. The resulting carbon is then added to a small diamond seed before it undergoes a similar HPHT process as any synthetic diamond.
Labs will add a fair amount of “generic” carbon that’s not sourced from the cremated remains, however. This is because the ashes will still contain impurities that can affect the color and clarity of the diamond. In fact, the so-called “personal carbon” from the cremated human remains will only make up around 10 to 15 percent of the total carbon in the finished product.
There’s a wide range of companies that will allow people to turn cremated remains into a diamond. Prices depend on quality, but a cremation diamond typically ranges from $750 to $20,000, according to the Cremation Institute.