Between December 11 and 14, 1972, Apollo 17 astronauts Eugene Cernan and Harrison "Jack" Schmitt explored the edges of Mare Serenitatis (Sea of Serenity), a dark plain on the Moon's surface. During a moonwalk, Schmitt, a geologist, saw a rock which stood out from the others due to its large size and lack of typical crystallization. That 3,8 billion-year-old rock, older than 99% of the rocks found on Earth, provided the fragment exhibited here.
