Get to know Dale Vince. He claims to have developed the world's only diamonds to be made from carbon, water and energy sourced directly from the elements at a sky mining facility in Stroud. I hope he succeeds.
Useful links: https://www.theguardian.com/environment/2020/oct/30/ecotricity-founder-to-grow-diamonds-made-entirely-from-the-sky I https://www.ecotricity.co.uk