The Christian Science Monitor reports
that Russia recently declassified news that it has an asteroid crater with trillions of carats worth of diamonds in it. These diamonds are apparently enough to supply global markets for the next 3,000 years. The Monitor
syas the crater was discovered in the 1970s nin the Popigai asteroid crater
The type of diamonds in the crater are known as impact diamonds. Gizmodo notes
that these diamonds are not useful for jewelry, but very useful in the tech industry, such as in making lasers. They are formed when a meteor or comet strikes Earth and carbon is fused into diamond. However, they have never been found on such a large scale. Life's Little Mysteries explains
how the diamonds in the crater may have been formed. It also quotes Richard April, a professor of geology at Colgate University, as saying a meteorite-impact crater with this many diamonds in it is "kind of unlikely."
A 2004 Geology report on the Popigai crater (which mentions impact diamonds) can be found here
. An article about how diamonds form can be found here