Carbon that may have been alive

Graphite inclusions in a Jack Hills zircon dated to 4.10 ± 0.01 billion years have a carbon-13 depletion of −24‰, the kind of fractionation produced by living things. If biological, it moves the origin of life some 300 million years earlier than previously argued, into a period thought too hostile. Abiotic processes can produce similar signatures, so the finding is suggestive rather than conclusive — but it is preserved in a crystal that can be dated exactly.