[Rockhounds] Diamonds need an electric zap to crystallize deep inside Earth

[Kreigh Tomaszewski]

Before diamonds can begin growing deep underground in Earth's mantle, they
need a little zap from an electric field, a new study finds.

In lab-based experiments, scientists mimicked conditions in the mantle —
the layer just beneath Earth's <https://www.livescience.com/earth.html> crust
— and found that diamonds grew only when exposed to an electric field, even
a weak one of about 1 volt, according to the study, which was published
online Jan. 20 in the journal *Science Advances*
<https://advances.sciencemag.org/content/7/4/eabb4644>.

"Our results clearly show that electric fields should be considered as an
important additional factor that influences the crystallization of
diamonds," study lead researcher Yuri Palyanov, a diamond specialist at the
V.S. Sobolev Institute of Geology and Mineralogy of the Siberian Branch of
the Russian Academy of Sciences, and at Novosibirsk State University, *said
in a statement*
<https://www.gfz-potsdam.de/en/media-and-communication/news/all/article/diamonds-need-voltage/>
.

The researchers gathered the starting ingredients needed to make a diamond
— carbonate and carbonate-silicate powders that are similar to
carbonate-rich melts abundant in the mantle. They put these powders in an
artificial mantle in their lab and subjected them to pressures of up to 7.5
gigapascals and temperatures of up to 2,912 F (1,600 C), and
electrode-powered electric fields ranging from 0.4 to 1 volt. After varying
periods lasting up to 40 hours, diamonds (and their softer carbon-based
cousin, graphite) formed, but only when the researchers set up an electric
field of about 1 volt — which is weaker than most household batteries.

Moreover, the diamonds and graphite formed only at the cathode, or the
negative part of the electric field. This spot provides electrons to
jumpstart a chemical process — mainly, so that certain carbon-oxygen
compounds in the carbonates can undergo a series of reactions to become
carbon dioxide and, eventually, the carbon atoms that can form a diamond.

https://www.livescience.com/diamonds-need-magnetic-field-voltage.html