Vanishingly few traces of the early Earth are known, so when a new source of zircon crystals of Hadean age is discovered, it makes a big difference to what we can infer about that eon.  In the podcast, Nadja Drabon describes how she analyzed the new zircons she and her colleagues discovered and what they reveal about the Earth’s crust between about 4 and 3.6 billion years ago.Nadja Drabon is Assistant Professor of Earth and Planetary Sciences at Harvard University.For podcast illustrations and more about Geology Bites, go to geologybites.com.