A team of researchers has reported the first laboratory synthesis and recovery of bulk hexagonal diamond, a crystal form long predicted to be harder than the conventional gems used in cutting tools ...

A pair of diamonds that formed hundreds of kilometers deep in Earth’s malleable mantle both contain specks of materials that form in completely opposing chemical environments—a combination so unusual ...

Jeweler Harry Winston donated the famous Hope Diamond—the largest-known deep blue diamond in the world—to the Smithsonian Institution in 1958. It arrived in a plain brown package by registered mail, ...