Diamonds may be forever, but that doesn't mean they won't lie about their age. A new study reveals that gems that were once believed to be the world's oldest diamonds are actually fragments of polishing grit left behind by some other scientists.

The itty-bitty jewels were found in 2007 embedded in zircon crystals from Australia's Jack Hills region. The discovery would have had huge implications for geologists: since zircons were the first rocks to appear on the surface of the earth back in its wild teenage years, they're basically the planet's time capsules. The tiny diamonds, estimated to be as ancient as 4.3 billion years old, would have proved that the early earth was much cooler in temperature than previously thought.

And it's a theory that will have to remain a theory. As it turns out, the scientists who found the rocks had used a synthetic diamond paste to polish them in preparation for lab work and later mistook their own tool for a major scientific discovery. Synthetic diamonds may appear similar to natural ones, but they have none of the rough edges found on the earth's version.

The original "discoverers" are not fighting the findings, which are based on photographic evidence and pretty hard to dispute. In the words of one of the debunking study's researchers, "Polishing the specimens with grinding compound that was made of diamonds was a terrible mistake."

[image, of different diamonds, via AP]