There was a jeweller, expert, prudent, and rich, three essential qualities in a jeweller. One day, after having washed his hands, this man sat at a table, when, glancing at a ruby ring he wore on his finger, he remarked that the stone, which usually delighted the eye with its splendor, had lost its brilliancy and become dull. Since he believed what others had related to him, he was firmly persuaded that some misfortune threatened him, and, having removed the ring from his finger, he placed it in its case. A fortnight later, one of this man’s sons died of varioloid. Reminded by this event of the phenomenon observed in the ruby, the jeweller took it from the case and found, on examination, that it had regained its pristine brilliancy. This fact confirmed him in his belief in the ominous quality of the stone. Once more, shortly after washing his hands, he remarked anew that the splendor of the ruby was dimmed, and he again fell a prey to anxiety, lest some fresh misfortune was impending. Since, however, his apprehensions proved vain and no untoward event happened, he investigated the matter carefully, and discovered that the obscuration of the color was due to a drop of water which had penetrated between the ruby and the foil, as the jewellers call it, and that the former brilliancy returned when the water had evaporated. The ominous character of the onyx is especially noted in Arabic tradition, as is shown by the Arabic name for the stone, _el jaza_, “sadness.” The following passage from pseudo-Aristotle offers an illustration of the strength of this prejudice against the onyx, which was said to come from China and the Magreb:[234] Those who are in the land of China fear this stone so much that they dread to go into the mines where it occurs; hence none but slaves and menials, who have no other means of gaining a livelihood, take the stone from the mines. When it has been extracted, it is carried out of the country and sold in other lands. Those men of the Magreb also who are gifted with any wisdom will not wear an onyx or place it in their treasuries. Indeed, no one is willing to wear it, unless he be bereft of his senses; for whosoever wears it, either set in a ring or in any other way, will have fearful dreams and be tormented by a multitude of doubts and apprehensions; he will also have many disputes and lawsuits. Lastly, whoever keeps an onyx in his house, or places it in a vessel, or puts it in food or drink, will suffer loss of energy and capacity.