ROCK CRYSTAL is a pure, translucent variety of quartz, possessing a double refraction of light. It is usually white in color but at times brown, black, or yellow. While we know this, the world for long centuries labored under the misapprehension of the ancients, stated by Pliny in his famous Natural History and quoted by Sir Thomas Browne in his work on Vulgar Errors, that “Crystal is nothing but snow or ice concreted, and, by duration of time, congealed beyond liquation.” Perhaps it was this unique quality of the rock crystal, as well as its peculiar natural beauty, which gave it value in the ancient world; for while crystals have been and are found in many places on the earth’s surface, fine pieces capable of being fashioned into vessels of sufficient size have ever been sought for.

Among the Egyptians and the Assyrians it was used to some extent for sacred scarabs and cylindrical seals and among the Greeks and the Romans for intaglii a fact sufficiently attested by the few we have in modern collections. The Greeks also fashioned the crystal into vases, some examples of early date coming from Cyprus. But it was above all at Rome in the period of greatest luxury under the Empire, that this precious material came to be regarded as of extreme value and to be sought for, so that it might be worked into drinking cups. A mania took possession of the fashionable world, enormous sums being paid for perfect vessels. We know that Nero, in-formed that his Empire was lost to him, dashed to the ground two crystal bowls engraved with scenes from Homer, that the world should be the poorer by their loss and that he might in some degree revenge himself upon mankind.

With the decline and fall of the Empire the demand and the art declined, yet we find mention of crystals here and there through all the Middle Age in chronicles and inventories. We read that Gregory X, in 1271, sent by Marco Polo “many fine vessels of crystal as presents to the Great Khan,” the most splendid and precious things that the Pope could command.

But it was at the beginning of the fifteenth century that rock crystal again came into its own, reaching the height of its popularity and technical perfection in the sixteenth century. It is to this finest period that the pieces in this collection belong, the work of two schools, the Italian and the German.

The first piece in date (CASE B) is a Covered Cup of German workmanship, the only fifteenth-century example in this collection. The cup is cut to twelve faces, each decorated with circular depressions, the foot supported by three putti, the whole mounted in silver gilt, set with jewels of a barbaric beauty sapphires, rubies, emeralds, and pearls. The significant fact is that the cup exhibits no traces of the engraver’s art and shows plainly that the Gothic traditions have not as yet lost their force. In general, we may say that the crystal workers of the fifteenth century relied very little upon the engraver. It remained for the artists of the sixteenth and later centuries to add the beauties of engraving to their other resources. Compare this piece with the Covered Cup in the same case, also of German workmanship, but of the sixteenth century. Here there is no trace of Gothic influence. The Renaissance spirit has triumphed and the cup is engraved with the most graceful of floral arabesques. The other pieces in CASE B, the Ewer of German workmanship, set with rubies, and the Reliquary of Italian workmanship, are also of the sixteenth century. This reliquary, oval in form, is deco-rated with a panel representing the Annunciation, in verre eglomisé, a term that has come to be used for all painting on the reverse of glass or rock crystal, so called from a French artist, Glorni, of the eighteenth century, who rediscovered or reapplied an old art.

In the other case (CASE A) are gathered the principal pieces, an extraordinary collection of sumptuous works; two Pricket Candlesticks, doubtless intended for an altar of importance, their bases of silver gilt decorated with delightful figures of animals in repoussé work; in the center a Tazza, remarkable not only for size and beauty of proportion, but for the enameled gold setting, jeweled with rubies, sapphires, and pearls.

A very important piece, the Bénitier portatif, or portable holy water stoup, formed part of the ecclesiastical furniture of the great Spanish cathedral of Valencia, used in its ceremonials, carried by an acolyte as the priest sprinkled the congregation with the holy water before the celebration of the high mass. I t is of perfect form, the body gadrooned and engraved with floral festoons, the handle mounted in gold enameled in beautiful colors and set with pigeon-blood rubies. Another noteworthy piece is the Plate attributed to Valerio Belli, called Il Vicentino, whose work marks the culmination of the engraver’s art in the first half of the sixteenth century, Vasari referring to hint with extreme praise. He was noted for his intaglii modeled on the antique and for numerous works in rock crystal, his services being sought by popes and princes. This piece merits the attribution by the refinement of its technique and a classical treatment closely resembling the workmanship in pieces definitely known to be from his hand.

The Pax came from a chapel in the Cathedral of Avila in Spain. This is of unusual beauty, probably of Milanese workmanship. In design it corresponds to a type generally introduced in the fourteenth century when the pax took a form inspired by the architecture of the period. In the same manner this pax, dating as it does to the sixteenth century, reflects the more florid architectural fancy of the High Renaissance. The central representation of the Adoration of the Magi is in verre eglomisé, framed in gold set with pigeon blood rubies, which vie with the glowing colors in the robes of our Lady, Saint Joseph, and the three Magi. The plinth and the entablature are decorated with circular medallions in verre eglomisé, representing a Doctor of the Church, Saint John, Saint Peter, a Bishop, Mary Magdalen, and Saint Francis. The entablature is surmounted by Saint George and the Dragon in enameled gold.

In the early Christian church before the celebration of the Eucharist, the Bishop saluted the congregation with the words, “The peace of God be with you,” the congregation answering, “And with thy spirit.” Thereupon the deacon bade them salute each other with a Kiss of Peace in sign of a perfect reconciliation, the clerics embracing the bishop and the laymen each other, the men the men and the women the women. In the thirteenth century this practice had fallen into general disuse, partly owing to the fact that the church had departed from its original custom, the male and the female worshipers no longer being separated during the service. In lieu of this, the church substituted the pax, upon which the worshipers bestowed the Kiss of Peace the baiser de paix. Now the pax is not ordinarily used. The members of the clergy in the service of the mass give the Kiss of Peace as they did in the early church, but the congregation no longer takes part in the ceremony.

The four other pieces in CASE A, probably late sixteenth century, while lacking the perfection of the finest period, still show a splendid vigor of design and technique. Quite wonderful is the smoky crystal Ewer of German workmanship, particularly interesting as the only example in this collection of a uniquely beautiful and much prized variety of crystal. The three other pieces are of Italian workmanship, the Bowl with the dolphin handles, the Cup in the form of a lobed shell, an eagle resting on the lip, and the Rose Water Vase used to sprinkle the hands of the guests at the ceremonial banquets.