Central Americans regarded the emerald, which they associated with rain, as a pledge of fertility. The Aztecs called it quetzalitzli and associated it with the quetzal, the bird with long green plumage which was a symbol of the seasonal renewal of Spring. Emeralds were distinguished from green jade in that, unlike the latter, they were unconnected with the bloodthirsty ritual offerings to the high gods Huitzilopochtli and Tlaloc, personifications of the Sun at noon and the no less pitiless tropical storm. Their benign influence was also felt in Europe where, if Portal is to be believed, ‘superstition long attributed to the emerald the miraculous quality of easing childbirth’. By extension, it might well have had those aphrodisiacal qualities which Rabelais claims for it.
The Christian lapidary associated it in its maleficent aspect with the most dangerous inhabitants of Hell.
Medieval folklore, however, endowed the emerald with all its beneficent powers with which, of course, a little wizardry was mingled. In India, it was said that the mere sight of an emerald so frightened the viper or cobra that its eyes dropped out of its head. According to Jerome Cardan, if bound on the left arm, it acted as a preservative against witchcraft. According to a medieval manuscipt in Oxford, it set prisoners free, provided that it had first been consecrated, that is separated from its malign powers. In St John’s vision, the Ancient of Days appeared, seated on his throne. The Holy grail was a chalice carved from an huge emerald.
The emerald partakes. An excellent example of this may be seen in the equestrian statue of St George in the Treasury at Munich. This precious item of Baroque jewellery shows the saint, dressed in sapphire (heavenly blue) and riding a solar white horse, spearing an emerald dragon. This is an example of Christian tradition drawing a distinction between properties, designating the first as good and the second as evil. In it the blue of the sapphire confronts the green of the emerald, the latter symbolizing the black arts. Nevertheless, Christian tradition retains the ambivalent symbolism of the emerald, since it is also the Papal jewel.