Just in time for Christmas, geologists announce the discovery of a rare grapefruit-sized rock containing upwards of 30,000 diamonds surrounded by thousands of red and green garnet and olivine crystals. The diamonds are tiny, most just millimeter size, but the amazingly sparkly red and green rock would make a truly spectacular Christmas decoration.
The rock was found in Russia’s Udachnaya diamond mine and donated to science as the diamonds are so tiny they have no value as gems. The find was, however, great news for geologists, because the diamond-rich rock is a rare find. Researchers reported on the 30,000 diamond rock on Monday, December 15th at the American Geophysical Union’s annual meeting.
Statement from geologist
“The exciting thing for me is there are 30,000 itty-bitty, perfect octahedrons, and not one big diamond,” enthusaed Larry Taylor, a geologist at the University of Tennessee, Knoxville, who presented the findings. “It’s like they formed instantaneously.”
The huge number of diamonds, as well as the rock’s unusual Christmas coloring, should provide clues to Earth’s geologic history as well as the origin of the diamonds, Taylor said. “The associations of minerals will tell us something about the genesis of this rock, which is a strange one indeed,” he continued.
“The [chemical] reactions in which diamonds occur still remain an enigma,” Taylor noted in an interview.
More on the Russian rock with 30,000 diamonds
The number of diamonds in this rock is millions of times greater than in typical diamond ore, which averages 1 to 6 carats per ton, Taylor explained. A carat is a unit of weight close to one-fifth of a gram, or 0.007 ounces.
Scientists theorize that diamonds are created deep below Earth’s surface, in the mantle below the planetary crust. Over millions of years, powerful volcanic eruptions carry hunks of diamond-containing mantle to the surface. Most mantle rocks are, however, crushed and broken during the trip to the surface, typically leaving only loose crystals. The Udachnaya rock is a rare piece of mantle that survived the trip without being completely broken up.
Taylor and researchers at the Russian Academy of Sciences studied the Udachnaya diamonds. They first probed the rock with an X-ray tomography scanner, causing different minerals to glow in different colors in the X-ray images, with diamonds looking like dark black crystals.
The thousands of diamonds in the rock are clustered in a band. The clear crystals are close to 1 millimeter tall and are octahedral (shaped like two pyramids that are glued together at the bottom). The rock is also speckled with a little bigger crystals of red garnet, green olivine and pyroxene. A computer simulation developed from the X-rays suggests the 30,000 diamonds formed after the garnet, olivine and pyroxene minerals.