New research from Johns Hopkins University suggests that diamonds may not be as rare as once believed.

Using a chemical model, researchers from Johns Hopkins University found that these precious stones could be born in a natural chemical reaction that is simpler than the two main processes that up to now have been understood to produce diamonds.

"Diamond formation in the deep Earth, the very deep Earth, may be a more common process than we thought," Johns Hopkins geochemist Dimitri A. Sverjensky said in a statement.

Specifically, their model -- yet to be tested with actual materials -- shows that diamonds can form with an increase in acidity during interaction between water and rock.

Up to now, the common understanding has been that diamonds are formed in the movement of fluid by the oxidation of methane or the chemical reduction of carbon dioxide. Oxidation results in a higher oxidation state, or a gain of electrons. Reduction means a lower oxidation state, and collectively the two are known as 'redox' reactions.

"It was always hard to explain why the redox reactions took place," Sverjensky, a professor in the Morton K. Blaustein Department of Earth and Planetary Sciences in the university's Krieger School of Arts and Sciences, said.

These reactions require different types of fluids to be moving through the rocks encountering environments with different oxidation states.

The new research showed that water could produce diamonds as its pH falls naturally - that is, as it becomes more acidic -- while moving from one type of rock to another. The finding is one of many in about the last 25 years that expands scientists' understanding of how pervasive diamonds may be.

"The more people look, the more they're finding diamonds in different rock types now," Sverjensky said. "I think everybody would agree there's more and more environments of diamond formation being discovered."

The findings are detailed in the journal Nature Communications.