No One Can Agree on Whether a New Kind of Rock Is Actually a Rock at All

The assumption that rocks have to be old and hard is an "urban legend," says geologist Jan Zalasiewicz. Others, like shale, can be peeled apart by hand; these rocks are incredibly frail. Scientists should consider plastic, now a ubiquitous feature of the ocean, a kind of mineral, Zalasiewicz says.

Read at Slate Magazine