A ruby called sandastros is described by Pliny as containing stellated bodies which he compares to the Hyades; hence, says he, they are the objects of great devotion with the Chaldæi or Assyrian Magi. According to Morales (De las piedras preciosas), the ruby and the diamond were both under the influence of the sign of Taurus; the same writer informs us that the Hyades and the sun were supposed to have a potent effect upon the ruby or carbuncle. In ancient Babylonia the sign of Taurus was regarded as the most important, and Winckler believes that the presence in this sign of the five stars of the Hyades and the seven of the Pleiades was brought into connection with the twelve-fold division of the zodiac. The Hyades signified the five signs visible in Babylonia at the summer solstice, while the Pleiades typified the seven invisible signs. It seems probable that the Pleiades were associated with the diamond, although Morales, who was very familiar with the Moorish astrology current among the Spaniards of his time, attributed the crystal to this group. His attribution proves at least that the stone of the Pleiades was a colorless one. In Sanskrit the diamond is called _vajra_, “thunderbolt,” and also _indrâjudha_, “Indra’s weapon”; another name is _açira_, “fire,” or “the Sun.”[448] All these designations are probably suggested by the brilliant flashes of light emitted by this stone. It is not easy to determine the reason that induced the Hindus to dedicate the diamond to the planet Venus rather than to the Sun or to the Moon. However, as the most brilliant of the planets, Venus was not unworthy of the honor, and if we substitute the Goddess of Love for her planet, it seems quite appropriate that she should be adorned with the most brilliant of precious stones. Certainly these sparkling gems are often enough offered at the shrine of Venus in our own day, and they often serve to win the good graces of the divinity to whom they are presented. The Sanskrit name for the sapphire, _nîla_, signifies “blue,” so that, as the topaz is the “yellow stone” _par excellence_, the sapphire is the blue stone (_nilaçman_). In both cases the name indicates a variety of corundum, distinguished merely by the coloring matter. As a talisman the Hindus believed that the sapphire rendered the planet Saturn favorable to the wearer, an important consideration from the astrological point of view, for Saturn’s influence was generally supposed to be unfavorable. The Hindus distinguished four classes of sapphires, corresponding to the four castes: Brahmins, Kshatriyas, Vaisyas, and Sudras. The respective sapphires were light blue, reddish blue, yellowish blue, and dark blue. The same distinction is made in the case of the diamond, and a like rule applies to both stones, namely, that only the appropriate stone should be worn by the members of each caste, in order to profit by the virtues inherent in the sapphire or diamond.[449]