I Come from Planet Tiffany....

"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."