A single Madagascan ammonite, sawn through its spiral and polished into two mirrored halves: the chambered shell of a sea creature some 150 million years old.
At a glance
Open your hand and a spiral sea lies in it. This ammonite swam Jurassic seas roughly 150 million years ago, and now it rests in two mirrored halves that still fit back together along the cut.