A deep theory of diamonds

New research on diamond formation suggests the valuable stones might actually be a dime a dozen - but good luck getting to these theoretical stones.

In a study published Tuesday in Nature Communications, scientists from Johns Hopkins University, present an alternative model for conditions under which diamonds can form.

Until now, it was thought that diamonds required complex chemical reactions called redox reactions (reduction and oxidation) involving the loss and gain of electrons as different kinds of fluids move through rock. But according to the new study, simple changes in pH (or acidity) can spur diamond formation, too.

The new model suggests that at very high temperatures (over 1,650 degrees Fahrenheit) and high pressures (over 725,000 pounds per square inch), water can form diamonds as it moves from one kind of rock to another. The key is the natural drop in pH - the water getting more acidic.

If these diamonds are forming, they're forming around 100 miles below the surface. So the scientists involved in the study will most likely never get to see these diamonds in the flesh.

Researchers hope their model can be used to study wider interactions between deep fluids and rock, helping scientists to better understand the way Earth's interior has evolved.