It was because the blue diamond was blue because it came from the ocean

by 350z33

It is said that diamond crystallized in the mantle at a depth of several tens of kilometers underground and was brought to the surface by volcanic eruption. Minerals called incrusions (impurities) contained in diamonds tell us where the diamond came from, but the latest research found inclusions contained in Blue Diamond , famous for Hope Diamonds in ancient seas It was found to be derived from boron .

Blue diamonds come from ocean floor that is pushed nearly to Earth's core | Ars Technica
https://arstechnica.com/science/2018/08/blue-diamonds-are-born-buried-deep-below-but-bear-ocean-bottom-boron/

Blue boron-bearing diamonds from Earth's lower mantle | Nature
https://www.nature.com/articles/s41586-018-0334-5

Among the diamonds, the blue and diamonds that are bluish are very rare, only 0.02% of the diamonds, but there are many different types of volcanic sediments, such as volcanic sediments of 1.2 billion years ago and volcanic sediments relatively new 90 million years ago It is found in the place. It is mysterious that it is extremely unusual for boron to make the diamond turn blue in the mantle, no matter if it is the outer shell of the earth. Wondering where the blue diamond is formed together was a question of many years.

Evan Smith et al. Of the Gemorological Institute of America (GIA) analyzed by crushing expensive diamonds to explore this. Analysis of diamond seems to be impossible with non-destructive methods such as X-ray and low power laser.

As a result of examining 46 blue diamonds, we found that blue diamond does not contain common minerals contained in ordinary diamond formed under the continental plate. The more minerals are deep underground, the more it will become unstable when levitating to the ground, making subsequent identification difficult. From this and other observations, we found that blue diamonds are generated at locations deeper in mantle than normal diamonds, where the depth is 660 km or more corresponding to the lower mantle.

However, here there are conflicting facts that "Blue diamonds are formed in the deep position of the mantle, but boron colors diamonds blue on the ground".

According to plate theory , the plate is pushed deep into the bottom of the ocean and finally recycled to the bottom of the mantle. It is thought that substances on the surface of the earth are also recycled at the same time, but the chemical evidence has been dilute until now.

However, since the Blue Diamond contained basalts that seemed to have made oceanic plates in addition to boron, the researchers said, "Since the submarine plate got underground and carried the boron deep into the mantle, it was blue, Diamonds were made ", he said. After that diamond rises from the ground with a slow motion and appears on the ground surface with the eruption. Because boron is taken into the oceanic plate by hydrothermal reaction with seawater, blue diamond is literally "blue of the sea".

by Yannis Papanastasopoulos