Agate
achates — the river’s stone
Theophrastus named it for the river Achates in Sicily, where the first banded stones rolled out of the hills. Agate builds in volcanic hollows layer by layer, each band a season of mineral water. China’s Nanhong — “southern red” — beds gave emperors their warmest carnelian-red agate; ours carries the same fire.
“Named by the Greeks for a river — every band a season of its current.”Theophrastus · On Stones, c. 315 BC