Our galaxy may contain high concentrations of tiny diamonds in carbon-rich planetary nebulae. That's the finding of a group of researchers from the Institut d'Astrophysique Spatiale in Paris.The group theorized that the low pressures and temperatures inside the nebula give birth to diamonds. Conversely, it is high temperatures and pressure that foster diamond growth on Earth. The difference may lie in the presence of a tiny molecule called adamantane that serves as a precursor for diamonds on Earth and may be present in late-stage stars. The group concedes, however, that these findings are preliminary and open to dispute. "In some of these nebulae, an infrared spectral characteristic has been observed and remains unexplained," said Louis d'Hendecourt, head of the research team. "Up to now, no convincing explanation has been given [for] this observation." If the group's theories prove correct, up to 10 percent of the dust that envelops these stars could be diamonds.