CRISTALLO nell'ARTE. — Rock crystal (colorless transparent quartz) has been known since antiquity as a material for shaping small objects. Figurines or carvings in crystal with secular subjects are frequently found in the early Christian period in the Roman catacombs (Vatican, Museum of Profane and Christian Art). Larger than usual are two lions’ heads, probably created for the decoration of a piece of furniture, now preserved in the Cluny Museum in Paris. Undecorated pieces of crystal were used in barbarian goldsmithing and subsequently in Merovingian art. Objects of crystal with religious representations are extremely rare; for example, a fish (Vienna, Museum) and a carving with the Adoration of the Magi (Vatican, Museum of Sacred Art).
In the early Middle Ages, the use of crystal became more frequent, both for religious and for secular objects.
Some carvings from the Carolingian period reproduce classical forms, including technically. Notable is the seal of King Lothair in the Aachen cross, consisting of a disk with the story of Susanna (London, British Museum), which was perhaps worked in Metz. But the great majority of medieval crystal objects are of Eastern origin. Many were brought to Europe during the Crusades, such as those in the treasury of S. Marco in Venice. Indeed, in almost all the great treasuries, besides those in Venice, Aachen, Essen, Quedlinburg, Bamberg, Capua, and the museums of Paris, London, and Nuremberg, these Eastern works are found; generally they are glasses, cups, ampoules, plates, flasks, or pendants. The name of the caliph of Egypt appearing on a jug in Venice and on a lunula in Nuremberg demonstrates that these crystal objects are largely Egyptian works of the 10th–12th centuries. Another group of tall, simply shaped, undecorated vessels was instead probably made at the Norman court in Palermo and shows the influence of Fatimid art.
Another center for crystal work developed in Venice. Its characteristic feature is filigree decoration, as can be seen in the candelabra of Carlo II d'Angiò (Bari, Cathedral) or in a reliquary originating from S. Galla in Rome (Vatican, Christian Museum). Smooth pieces of crystal were also used in Venice to protect relics; such is the case with the ancient reliquary of the Volto Santo in Rome (Treasury of S. Pietro), donated by two Venetians in 1350. Sometimes crystals were placed over miniatures to protect them and give them the brilliance of enamels, as in the triptych of Alba Fucense (Rome, Palazzo Venezia), or they were placed at the center of large crosses (Assisi, Atri, Pisa).
In the northern countries, crosses, reliquaries, and crystal jugs were also worked during the Middle Ages; this is mentioned in a document of 1260 discovered in Paris, while some fine crystal jugs appear to have been made at the court of Burgundy.
At the beginning of the sixteenth century, a school for working crystal flourished in northern Italy. The Head of Lucretia in Vienna (Lederer Collection), attributed to Tullio Lombardi, is very famous. For the most part, these carvings were intended to be inserted into caskets (for example, the Farnese casket in the gallery of Naples by Giovanni Bernardi, and a small chest by Valerio Belli in the Palazzo Pitti in Florence), into crosses or candelabra (v. Rome). Other crystal objects, such as pax tablets, crosses, or simple plaquettes, are found in all the great collections. A fine portrait of Alessandro de' Medici, made by Domenico di Polo, is now in the National Library of Paris. In Germany this art was imported from northern Italy. Artists such as the Miseroni from Milan worked in Prague, while the Saracchi worked in Munich. Francesco Gundelach' derives his art from their influence. A major center of crystal production developed in Bohemia as early as the sixteenth century. In the seventeenth century, glass, being less expensive, contributed to the decline in the production of worked crystal. Only for the decoration of chandeliers (toward the end of the eighteenth century), and during the Neoclassical period for the execution of highly refined carvings, was this noble material once again occasionally used. — Vedi tav. LVI.