"UCLA paleobiologist J. William Schopf and colleagues have produced 3-D images of ancient fossils -- 650 million to 850 million years old --preserved in rocks, an achievement that has never been done before.
If a future space mission to Mars brings rocks back to Earth, Schopf said the techniques he has used, called confocal laser scanning microscopy and Raman spectroscopy, could enable scientists to look at microscopic fossils inside the rocks to search for signs of life, such as organic cell walls. These techniques would not destroy the rocks."
Nice photos in article.