It’s been eighteen months since we mentioned the Deep Carbon Observatory (DCO), a multidisciplinary effort to plumb the depths of “deep carbon”—the ninety percent of not-readily accessible carbon in our world (see “Carbonated Leverage“). In December, we received an announcement about the related Carbon Mineral Challenge, which invites professional and amateur mineral collectors to join the carbon quest. “New research predicts at least 145 of Earth’s carbon-bearing minerals remain undiscovered,” the announcement states. “How many can collectors find by 2019?” That’s when the ten-year hunt officially ends. A midterm scientific report was issued in December 2014.