The analogy between the flame of a lamp or the glow of a burning coal and the radiance of a ruby, suggested some of the names given to this stone, or those resembling it in color, as, for instance, the Greek anthrax and the Latin carbunculus and lychnis. Probably the fancy that such stones were luminous in the dark was nothing more than the logical result of the quasi-identification of them with fire in some of its manifestations. Still, it is a well-known fact that some stones possess a high degree of phosphorescence. This circumstance must have been observed by chance, and may have had something to do with the legends of luminous stones, although this peculiarity is not characteristic of the ruby.
According to Pliny, the lychnis, perhaps a spinel, was so called a lucernarum accensu (from the lighting, or the light, of lamps). The author of the poem “Lithica” says that the diamond (adamas), like the crystal, when placed on an altar, sent forth a flame without the aid of fire.[240] If this did not refer to the use of rock-crystal as a burning-glass, we might see in the passage an indication that the phosphorescence of the diamond had already been noted before the second or third century of our era.
From the Lydian river Tmolus a marvellous stone was taken which was said to change color four times a day. This surpasses the properties of the “saphire merveilleux” which changed its hue at night. Only innocent young girls could find the Lydian stone, and while they wore it they were defended from outrage.[241] Is it possible that the ancient writer intended to hint at the proverbial fickleness of woman, when stating that this changeable stone could only be discovered by one of the fair sex?
The temple of the Syrian goddess Astarte contained an image of this divinity crowned with a diadem in which was set a luminous stone. Such was the splendor of the light emitted by this gem that the whole sanctuary was lighted up as though with a myriad of lamps. Indeed, the stone itself bore the name lychnos (“lamp”). In the daytime this light was fainter, but was still very noticeable, as a fiery glow.[242]
Two fabulous stones are noted by pseudo-Aristotle, and one of these, the “sleeping-stone,” must have possessed marvellous soporific power. It was a luminous stone of a bright ruddy hue, and shone in the darkness with a bright light. If a small quantity of this stone were hung about a person’s neck, he would sleep uninterruptedly for three days and nights, and, when awakened on the fourth day, he would still be almost overcome by sleep. The other stone, of a greenish hue, had the opposite quality and induced prolonged wakefulness; so long as it was worn, sleep was banished. Our author gravely states that “some men who must watch at night suffer greatly from lack of sleep.” If, however, they wore the “waking-stone,” they suffered no inconvenience from their enforced vigils.[243] Evidently this stone would be a precious possession for night-watchmen, and a more satisfactory guarantee for their employers than “timeclocks” or other tests of wakefulness.
In his commentary on Marbodus, Alardus of Amsterdam relates the history of a wonderful luminous stone, a “chrysolampis,” which, with many other precious stones, was set in a marvellous golden tablet dedicated to St. Adelbert, apostle of the Frisians and patron of the town of Egmund (d. 720-730), by Hildegard, wife of Theodoric, Count of Holland. The gift was made to the Abbey of Egmund, where the saint’s body reposed. Alardus tells us that the “chrysolampis” shone so brightly that when the monks were called to the chapel in the night-time, they could read the Hours without any other light. This wonderful stone was stolen by one of the monks, whom Alardus terms “the most rapacious creature who ever went on two legs”; but, fearing to keep so valuable a gem with him, he cast it into the sea and it was never recovered.[244]
Strange tales were told of a luminous “carbuncle” on the shrine of St. Elizabeth (d. 1231) at Marburg. This stone was set above the statuette of the Virgin, and it was said to emit fiery rays at night. However, Creuzer informs us that it was only a very brilliant rock crystal of a yellowish-white hue. The shrine was an elaborate work of art in silver gilt, and was literally covered with precious stones to the number of 824, besides two large pearls and a great many smaller ones. All these gems were stripped from their settings when the shrine was taken from Marburg to Cassel in 1810.[245]
At the Dusseldorf Exhibition of 1891, the writer saw what was called “The Ring of St. Elizabeth,” purporting to be set with her miraculously luminous ruby. The stone in the setting proved, however, to be a large almost flat carbuncle garnet of no great brilliancy, set in a narrow rim of gold.
After noting the reports of medieval travellers regarding the wonderful luminous rubies of the sovereigns of Pegu and repeating the tale that the night was illumined by their splendor, Cleandro Arnobio adds that it did not appear that any such rubies were to be found in his day. Nevertheless, he had heard from an ecclesiastic of a certain jewel that shone brightly at night. This stone, however, was not a ruby, but was of a pale citron hue, and hence Arnobio inclines to believe that it was either a topaz or a yellow diamond.[246] This probably refers to the Marburg “carbuncle.”
The luminous “ruby” of the King of Ceylon is noted by Chau Ju-Kua,[247] a Chinese writer of about the middle of the thirteenth century and hence a contemporary of the Arab Teifashi. He says: “The king holds in his hand a jewel five inches in diameter, which cannot be burned by fire, and which shines in the night like a torch.” This gigantic luminous gem was also believed to possess the virtues of an elixir of youth, for we are told that the king rubbed his face with it daily and by this means would retain his youthful looks even should he live more than ninety years.