Diamonds have been found in some of Earth's oldest rocks, dating back to 4.3 billion years ago. The precious gems are an exciting find for geologists, because they suggest that the planet's rocky ...

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 ...

A 37-carat diamond, half pink and half colorless, found in Botswana, intrigues scientists due to its two-stage origin and rare purity.

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, ...