Diamonds are made out of carbon — highly organized carbon, that is. Geologists are still guessing how diamonds formed in the ...

Eclogitic diamonds formed in Earth's mantle originate from oceanic crust, rather than marine sediments as commonly thought, according to a new study. Eclogitic diamonds formed in Earth's mantle ...

(CNN) — Pink diamonds are extremely rare and coveted — a now-closed mine in Australia has been the source of 90% of the colored gemstones. Polished pink specimens of the highest grade can sell for ...

Diamond, with its tough-to-break carbon lattice of interlocking cubes, is traditionally considered the hardest material on Earth. Yet a rare form of diamond known as lonsdaleite—a crystal with carbon ...