A Unusual, Beforehand Unknown Mineral Has Been Found in a Single Diamond Speck

Diamonds are rarely excellent. Like us, they carry blemishes and flaws: tiny ‘inclusions’ of historic chemistry trapped inside their lustrous frames.

To the jeweller, these minuscule marks could diminish a gemstone’s worth. To a scientist, the imperfection itself can really be the true glittering prize.

In a startling new discovery, researchers in Canada have discovered one thing the world has by no means seen earlier than: a beforehand unknown mineral with a really uncommon chemical signature, hidden inside a diamond from South Africa.

For such an enormous discovery, it is a surprise they discovered something in any respect.

Solely a single grain of this unusual new mineral – referred to as goldschmidtite – was discovered, with the entire mass contained in the diamond measuring simply 100 micrometres (roughly the width of a human hair).

The diamond encasing the goldschmidtite grain, earlier than breakage. (Meyer et al., American Mineralogist, 2019)

Regardless of its modest dimension, the fabric contained inside this speck is wholly new to science. It provides a singular report of chemistry from a very long time in the past, contained in the deep, historic elements of the planet, the researchers say.

“Goldschmidtite has excessive concentrations of niobium, potassium, and the uncommon earth parts lanthanum and cerium, whereas the remainder of the mantle is dominated by different parts, corresponding to magnesium and iron,” explains College of Alberta PhD scholar Nicole Meyer.

“For potassium and niobium to represent a significant proportion of this mineral, it will need to have fashioned underneath distinctive processes that concentrated these uncommon parts.”

The tiny pattern, which is dark-green in color, is estimated to have fashioned at a depth of about 170 kilometres (105 miles) beneath the floor, based mostly on geothermobarometric evaluation.

The mineral, formulaically often called (Ok,REE,Sr)(Nb,Cr)O3, is chemically just like an engineered perovskite-structured crystal referred to as potassium niobate (KNbO3), however is just the fifth recognized naturally occurring perovskite-group mineral ever seen in Earth’s mantle.

The goldschmidtite pattern – named in honour of the Norwegian geochemist Victor Moritz Goldschmidt (1888–1947) who helped to pioneer perovskite mineralogy – was retrieved from the Koffiefontein kimberlite pipe in South Africa’s Kaapvaal Craton.

Kaapvaal Craton is residence to among the oldest rocks on the planet, giving scientists fertile territory for all kinds of mineral discoveries, a few of which happen in diamonds.

And why not? If you are going to journey from very far underground into the very distant future, diamond makes for an honest time capsule, all issues thought-about.

“As a chemically inert and inflexible host, diamond can protect included minerals for billions of years,” the paper explains, “and thus present a snapshot of historic chemical circumstances in cratonic keels or deep-mantle areas.”

The findings are reported in American Mineralogist.