I found this interesting article on CNN just a couple of minutes ago. The geology of it all makes sense, but I seriously doubt that it has any serious interest beyond that. And it wouldn't be a treasure there. No, Quarz would most likely become the really valuable thing if silicon is absent, which is a dominant component of the Earth's crust. Diamonds really aren't that valuable anyway, mainly because the prices have been artificially inflated by dealers over human history.
Other Planets in Galaxy May Have Layer of Diamonds
WASHINGTON (Reuters) - Some planets in our galaxy could harbor an unexpected treasure: a thick layer of diamonds hiding under the surface, astronomers reported on Monday. No diamond planet exists in our solar system, but some planets orbiting other stars in the Milky Way might have enough carbon to produce a diamond layer, Princeton University astronomer Marc Kuchner said in a telephone news conference. That kind of planet would have to develop
differently from Earth, Mars and Venus, so-called silicate planets made up mostly of silicon-oxygen compounds. Carbon planets might form more like some meteorites than like Earth, which is believed to have condensed from a disk of gas orbiting the sun.
In gas with extra carbon or too little oxygen, carbon compounds like carbides and graphite could form instead of silicates, Kuchner said at a conference on extrasolar planets in Aspen, Colorado.
Any condensed graphite would change into diamond under the high pressures inside carbon planets, potentially forming diamond layers inside the planets many miles thick.
Carbon planets would be made mostly of carbides, although they might have iron cores and atmospheres. Carbides are a kind of ceramic used to line the cylinders of motorcycle engines among other things, Kuchner said.
Planets orbiting the pulsar PSR 1257+12 may be carbon planets, possibly forming from the disruption of a star that produced carbon as it aged, he said.
Other good candidates for carbon planets might be those located near the galaxy's center,
where stars have more carbon than the sun. In fact, the galaxy as a whole is becoming richer in carbon as it gets older, raising the possibility all planets in the future may be carbon planets, Kuchner said.