iamonde comes from Inde and some from Arabie; that which cometh from Inde is clipped males, ye other female. The male is brown appon light shininge, ye female is whit and beutifull of coulor like Cristall. Thes diamonds is very pretious to thee and of great hardnesse, for they will grave in Iron or steele, taking no harme. If a man werre it, it strengthen him and kepith him from dreming in his sleep, from faintnes and from poyson, from wroth and chiding. It sendeth and helpeth men to great worth. It defendeth a man from his enemies, and keepeth a man in good estate when he findeth him; it comforte a man witt, and support him of ritches. And though a man do fall downe from a cart or a wale he shall not break any of his bones if the stone be on him... It destroyth Lechery; and he shall not lightly be acombred so yt he feare god. And it will keepe the seede of a mans body within a womans body, so yt the children's limmes shall not be wrong ne crooked. And it must be sett in the mettle and bore of a mans left halfe"

Anglo-Norman document, the "Sloane Lapidary" (1243).