Sources : Magnet
Aberdeen Bestiary [13th century CE] (folio 102v): Lodestone is found in the land of the cave-dwellers and in India. It has a metallic color and attracts iron. Its virtue is that if a man wants to know if his wife is chaste or not, he should place the stone under her head when she is asleep; if she is chaste, she will embrace him warmly; otherwise, she will fall from the bed as if struck by a hand; this happens because of the odor of the stone. If a thief should enter a house to rob it, and should place in different parts of the house a live coal and on top of it powdered lodestone, so that it gives off smoke to the four corners of the house, it will seem to those who are in the house that the house is collapsing; as a result, they will flee and the thief can rob the place. Lodestone produces harmony between man and woman; it bestows grace, eloquence, skill in argument. If it is given in the form of a drink, it purges dropsy. Its powder, put on a fire, quenches it.