WASHINGTON — Blue diamonds —like the Smithsonian’s famous Hope diamond— are the rarest of all. But how they formed more than a billion years ago is a bit of a mystery. Now scientists think they have a glimmer of an answer.
Their research published Wednesday found blue diamonds form deep inside the Earth — deeper than other diamonds.
The scientists scrutinized imperfections in nearly four dozen of the gemstones. They examined tiny slivers of rock encased in the diamonds — virtual time capsules from the moment the diamonds were formed. The composition of the minerals reveals that blue diamonds are formed at extraordinary depths in the Earth.
Their striking blue colour comes from traces of the element boron.