Dear 100 Hour Board,
How many diamonds can the average human's ashes be used to make?
-Out of Service
So, there's not really that much carbon in cremated remains of humans. And in addition, the amount of carbon in the ashes would certainly vary depending on the method of cremation. Most cremated remains would have very small amounts of carbon, effectively almost none. As Ento states in question 86985, most of the carbon is burned off and calcium phosphate remains. However, apparently there are some ways to get more carbon. If you're interested in reading a creepy patent application, here's a patent application for "making synthetic gems comprising elements recovered from complete or partial human or animal remains and the product thereof ". Apparently they collect carbon dioxide and cremate the body in a way that leaves more carbon than traditional cremation. There seem to be a couple ways proposed in which to do this. Now, they don't give any specific numbers on how much carbon they can get from a body with these processes, but let's assume that their filtration system is really good, and it gets all of the carbon from the body.
The average human body is 18.5 percent carbon by mass, and the average mass of a human is 70 kilograms. So the average human has about 13 (12.95) kilograms of carbon. So that's a lot of carbon, and I suppose they could grow a lot of diamonds with that carbon. The carbon would be purified and graphetized before being turn into diamonds. I guess if you had 13 kilograms of pure carbon, you could eventually grow 13 kilograms of synthetic diamond, but that would be a very long and expensive process, so I wouldn't plan on being turned into 13 kilos of diamond very soon.
Keep it real,