A famous Scotch amulet was a polished globular mass of white quartz, an inch and three-quarters in diameter, owned by the chiefs of Clan Donnachaidh and known as the “Stone of the Banner.” It had been accidentally found by a chief of this clan, who, on his way to join Robert Bruce in 1315, before the battle of Bannockburn, noted a glittering stone embedded in a clod of earth that had become attached to his flagstaff. It was looked upon as a powerful talisman in battle, and water in which it had been dipped was said to cure diseases. Tradition asserted that this white stone of Clan Donnachaidh was identical with that used long before by St. Columba.[42] As such white stones were often deposited in graves, sometimes even being placed in the mouth of a deceased person, it has been suggested that perhaps the sparks emitted by the quartz on percussion were believed to shed some faint gleams along the dark pathway of the departed in his journey to the underworld. In Christian times there can be little doubt in regard to the influence exercised by the text in Revelation: “To him that overcometh ... I will give a white stone, and in the stone a new name written, which no man knoweth save he that receiveth it.”[43] Crystal balls are not only valued for the visions to be seen, or supposed to be seen in them, but are sometimes worn as amulets against illness. In some parts of Japan they are thought to ward off dropsy, and their wear is also recommended to guard from all wasting diseases.[44] The likeness of rock-crystal to congealed water may well be credited, in the doctrine of sympathy, with its putative power of preventing the watery infiltration from which a dropsical patient suffers. As the Japanese make many choice crystal balls, these objects are generally more or less familiar in that land and have thus appealed as well to those who were superstitious as to those who appreciated things beautiful in themselves.