A rock filled with 30,000 diamonds has been found in a diamond mine in Russia, just in time for Christmas. Even the rock itself seems to have followed a Christmas theme, coloured red and green from the garnet, olivine and pyroxene minerals that make up the rest of the rock.
Although too small to be of any value as gems, the diamonds have made a great present to scientists this year. The rock, only about the size of a grapefruit, could hold the key to unravelling how diamonds form.
On Monday 15th December at the American Geophysical Union’s annual meeting, geologist Larry Taylor from the University of Tennessee reported the recent finding that came from the Udachnaya diamond mine. He described the 30,000 diamonds as ‘itty-bitty, perfect octahedrons’, saying it seemed ‘like they formed instantaneously’. This is what makes the discovery so much more exciting for science than finding one large diamond. The crystals from this rock are only around 1mm tall, not nearly large enough to be cut into anything valuable. Instead, the rock has been donated to science.
When we think of diamonds we tend to just think of them as a piece of shiny jewellery, what we fail to see is the potential information that can be gleaned from them. Scientists don’t actually yet know exactly what chemical reactions cause diamonds to form. They think these diamonds are created deep below the surface in the mantle, and are subsequently brought to the surface during explosive eruptions of igneous rocks known as kimberlites. These new findings have suggested that they form from the fluids that escaped from subducted oceanic crust, and the outcomes will be published next month in a special issue of Russian Geology and Geophysics.
Author: Clare Stead
Ph.D. student, Department of Geology, Trinity College Dublin