There is found in the Pactolus a stone called argyrophylax which looks like silver. It is rather difficult to recognize it because it is intimately intermixed with the little spangles of gold which are found in the sands of the river. It has one very strange property. The rich Lydians place it under the threshold of their treasurehouses, and thus protect their stores of gold. For whenever any robbers come near the place, the stone gives forth a sound like a trumpet and the would-be thieves, believing themselves to be pursued, flee and fall over precipices and thus come to a violent death.
Pseudo-Plutarch, Treatise on Rivers and Mountains, quoted from: F.D. Adams, The Birth and Development of the Geological Sciences, New York, Dover, 1954, p.31.
PLACE: The river Pactolus, Lydia
TIME: Treatise written during Third Century