The Russian government has revealed that a vast quantity of high-quality diamonds rests beneath a Siberian impact crater, numbering in the "trillions of carats".

The Popigai crater, 100km-wide and located in the isolated north of the country, was formed roughly 35.7 million years ago by the impact of an asteroid estimated to be between five and eight kilometres wide. Its collision created a wealth of impact diamonds -- which form when an existing diamond seam is hit by a large falling body -- in such quantities that could, it is claimed, supply the world diamond market for the next 3,000 years.

According to the Christian Science Monitor, Nikolai Pokhilenko, the director of the Novosibirsk Institute of Geology and Mineralogy, has said that these diamonds are "twice as hard" as normal diamonds, making them ideal for industrial and scientific use. He also claimed that the supply under Popigai is ten times the size of the rest of the world's reserves, potentially holding trillions of carats. A carat -- defined as 200mg -- is the standard measurement of weight for precious gems and minerals.

The Popigai crater is the world's fourth-largest asteroid impact crater known so far, after the Chicxulub, Sudbury and Vredefort craters. The Soviet government reportedly discovered the deposits in the 1970s on a scientific expedition, but decided to keep the information secret so as not to disturb world markets and lower the value of their already-profitable Mirny mine further east, which at its height was producing ten million carats of diamonds per year.

David Fuller's view There have probably been more exaggerated stories from the mining industry than any other, so I would take this one with the proverbial grain of salt, especially if it turns out to be part of a promotional effort prior to a new share listing.

The claim that "these diamonds are 'twice as hard' as normal diamonds, making them ideal for industrial and scientific use", even if true, suggests that they are very small and not of gem quality. They would still have commercial value but if this was a really good diamond find, I think we would have heard more about it over the approximately 40 years since it was discovered.