A costly Chinese amulet consists of the diamond, the ruby, and the emerald, to which are added the pearl and coral; Oriental sapphire and topaz are classed with the ruby. An amulet containing these five substances is thought to combine the protecting influences of the different deities presiding over them, and is supposed to lengthen the wearer’s life. Sometimes these five princely gems are wrapped up in a paper bearing the names of the respective divinities, to which is added the name of the moon, and those of the twenty-seven constellations, or houses of the moon. Such an amulet, suspended at the entrance of a house, is believed to afford protection to the inmates.[25] In the language of the ancient Mexicans blood was called _chalchiuhatl_, or “water of precious stones,” as the quintessence of what were regarded as the most costly things.[26] Although such poetic designations are in modern times mere figures of speech, among primitive peoples they are more significant, and it is highly probable that with the Aztecs, as with other peoples, the wearing of precious stones was believed to enrich the blood and thus to promote health and vigor, for “the blood is the life.” That gems had sex is asserted by the earliest writers as well as by many of those of a later date. While this must usually be understood as a poetic way of indicating a difference in shade, the darker varieties being regarded as male and the lighter ones as female, Theophrastus, the earliest Greek writer on precious stones, clearly shows that this sexual distinction was sometimes seriously made, for he declares that, wonderful as it might seem, certain gems were capable of producing offspring. This strange idea was still prevalent in the sixteenth century, and ingenious explanations were sometimes given of the cause of this phenomenon, as appears in the following account by Rueus of germinating diamonds:[27] It has recently been related to me by a lady worthy of credence, that a noblewoman, descended from the illustrious house of Luxemburg, had in her possession two diamonds which she had inherited, and which produced others in such miraculous wise, that whoever examined them at stated intervals judged that they had engendered progeny like themselves. The cause of this (if it be permissible to philosophize regarding such a strange matter) would seem to be that the celestial energy in the parent stones, qualified by some one as “_vis adamantifica_,” first changes the surrounding air into water, or some similar substance, and then condenses and hardens this into the diamond gem. The pearl-fishers of Borneo are said to preserve carefully every ninth pearl they find, and place them in a bottle with two grains of rice for each pearl, believing, in spite of all evidence to the contrary, that these particular pearls have the power to engender and breed others. Custom and superstition require that each bottle shall have the finger of a dead man as a stopper.