MARBLE. — For sculpture, the marbles most commonly used are the white ones, known as statuary marble, among which the most prized are those with a fine grain that allow for more precise and delicate work. In antiquity, Greek marbles were renowned, especially the Parian marble; today, the extremely rich quarries of Carrara supply material to the entire world, already known in the 2nd century B.C. and exploited since the 12th century.
Only the Egyptians commonly used colored marbles for sculpture, of which they had an abundance: porphyry, granite, basalt, all very hard and resistant to the chisel, requiring extreme technical skill. Among the Greeks and Romans, their use was introduced only in later periods, almost always for decorative sculptures that sought an effect more of opulence than pure beauty (vases, kraters, furniture legs, etc.). Their use continued in the early Christian era: monumental porphyry sculptures from the 4th century include the two sarcophagi of St. Helena and St. Constantia, now in the Vatican Museums. For the same purpose of rarity and technical virtuosity, polychrome marbles were again used by sculptors in the late 16th century, and Vasari cites as examples of extreme skill three ovals in porphyry by Tadda, a sculptor from Fiesole, one with the head of Christ, the others with portraits of Duke Cosimo and Duchess Leonora. Similarly, about a century later, Algardi carved the delicate sleeping putto in the Galleria Borghese from touchstone (i.e., the very hard black ancient stone), a tour de force even among the virtuosity of the lavish 17th century. At that time, polychrome marbles were fashionable not only in decorative sculptures but also in accessories for funerary monuments (Rome, the monument to Gregory XV by Le Gros in S. Ignazio; that to Alexander VII by Bernini in St. Peter’s, etc.), and their use continued with extravagant excesses until the Neoclassical period reverted to the exclusive use of white marble.
In architecture, marble was used in ancient Greece as a building material, i.e., for the very framework of the structure; among the Romans, it was employed for revetment with ever-increasing splendor of polychromy and technique. Even for structural elements—columns, capitals, entablatures—polychrome marbles were used: granite (from which colossal columns were made, such as those of the Pantheon and the Baths of Diocletian, now S. Maria degli Angeli), cipollino, serpentine, porphyry, etc. In Paleochristian churches, these elements are often spolia (i.e., taken from pagan buildings), and thus columns of different materials and sizes are frequently found aligned together; however, in the churches of the Exarchate—in Ravenna, Grado, Parenzo—the greater wealth and construction possibilities allowed the use of marbles from Greek quarries specifically worked for this purpose. For decorative parts, Christian art continued and perfected techniques already in use in classical antiquity: opus tessellatum for floors, and with the addition of a few glass tesserae also for vaults (S. Costanza in Rome); opus sectile for wall revetment. It achieved a clear style in the delicate tracery technique, with flat ornaments on deeply recessed backgrounds, creating a striking chiaroscuro effect, for capitals and transennae.
Throughout the Middle Ages, architecture sought in marble a sober polychromy, usually combining white with a single color, sometimes two. The variety of coloristic effects in different regions is determined by the availability of local materials: thus the green marble of Prato and the portoro contribute to characterize, respectively, Tuscan and Ligurian architecture, in which they alternate in the facades and interiors of churches, creating bands
The part by far the largest of Morocco (398.6 thousand sq. km. with 9 million inhabitants) is represented by the Sultanate of Morocco, a French protectorate since 1912 and since 1947 included as an associated state in the French Union. Capital: Fez (201,000 inhabitants). In addition to a notable and varied agricultural production (barley, wheat, corn, and recently fruit, early vegetables, grapes, and olives), and a rich livestock heritage, the Sultanate boasts promising developments in the mining sector (phosphates, manganese, cobalt, lead, zinc, antimony, molybdenum), while the lack of raw materials for power (coal, oil) is offset by the hydroelectric potential of the Atlas Mountains.
Morocco is also a Spanish protectorate, under the control of a high commissioner. The territory essentially coincides with the Rif region (22 thousand sq. km.), inhabited by industrious agricultural populations (1.1 million souls), and notable from an economic standpoint for its rich deposits of iron minerals, as well as antimony, lead, and zinc, all concentrated in the hinterland of Melilla. Alongside the capital, Tetuan, which has 73,000 inhabitants, the two ports of Melilla (62,000 inhabitants) and Ceuta (50,000 inhabitants) remain important, together with the Alhucemas Islands, Chafarinas, and the Peñón de Vélez de la Gomera, which are detached from the actual protectorate, forming the so-called Presidios. For the geographical map V. AFRICA (I, cols. 707-708).
