When miners at the Udachnaya diamond mine in Russia saw the red and green stone they unearthed from the ground, they already knew the rock was different and for an apparent reason. The 30mm rock is studded with thousands of diamonds.
The bizarre-colored rock has 30,000 diamonds, a concentration a million times higher than normal. The stone, however, are too small to be used as gems so the mining company donated the rock to the Russian Academy of Sciences.
Although the diamond's tiny size makes them essentially worthless as gems, the rock is a rare and precious find for scientists. Larry Taylor, a geologist from the University of Tennessee, said that the number of diamonds on the rock as well as the stone's unusual red and green coloring can provide researchers with hints on the geologic history of the Earth. The one-of a kind characteristic of the stone can also shed more light on the origins of the precious gemstones.
"The associations of minerals will tell us something about the genesis of this rock, which is a strange one indeed," Taylor said.
Diamonds are one of the most sought after stones throughout history adorning royal crowns and jewelries and while the precious stone is now understood well enough it can already be produced by synthetic means in the laboratory, its natural origins are still shrouded in mystery.
To examine the diamond-rich rock, Taylor and researchers from the Russian Academy of Sciences used an X-ray tomography scanner and found that the diamonds clustering together measure just 1 millimeter and are octahedral, which means they are shaped like two pyramids that were stuck together at the base.
The researchers likewise found that the red and green color of the stone came from larger crystals of red garnet and green olivine and pyroxene. A three dimensional model built, based on the X-ray results, also revealed that the tiny diamonds formed after these three minerals. Taylor's team also found carbonate and garnet in the tiny capsules insides the diamonds.
The overall findings of the analysis of the Udachnaya rock suggest and add credence to the theory that the diamonds crystallize from fluids that escape from ocean crust, which was likely made up of a dense rock known as peridotite, as it was pushed by tectonic plates downward, a process called subduction.
Taylor said that the result is set to be published in a special issue of Russian Geology and Geophysics in January next year.