Earth’s most abundant mineral

American geologists have named the earth’s most abundant mineral Bridgmanite.

It had hitherto remained nameless as a large enough sample of the mineral, found in the earth’s lower mantle, had not been recovered. Under the rules of set down by the International Mineralogical Association, a mineral cannot be given a formal name until a specimen has been found and examined first hand.

A group of American geologists were recently able to extract a sample large enough to analyse from a meteorite.

The new name is in honour of Percy Bridgman, a pioneer in the use of high pressure experiments to better understand how many geological formations come about.

Bridgmanite makes up about 70 percent of the earth’s lower mantle and 38 percent of the total volume of the earth. It is made up of high-density magnesium iron silicate.

The lower mantle, which starts at 670 km under the crust, is difficult to access for samples.

The researchers looked at a meteorite that had fallen inside Australia in 1879 as a likely candidate for samples, and found what they were looking for.

Destructive technique

Scientists had looked at likely candidate meteorites in the past, but electron diffraction — the technique they used to look for perovskite — had always wound up causing it to be destroyed.

This time the team used a different, less destructive test — one that involved the use of a micro-focussed X-ray beam in conjunction with electron microscopy.

The researchers noted that the sample had more sodium and ferric acid than expected.

Their discovery is expected to aid future geological research, offer clues about what goes on when celestial bodies collide and potentially give hints about the formation of the universe.

The research paper was published in the journal Science.