Mosaic jewelry was made popular after the excavations of Pompeii and Herculaneum and was a type of souvenir jewelry termed "Archaeological." Mosaics made especially in Florence were known as pietra dura. They were constructed of small pieces of stone such as malachite, lapis lazuli, coral, opal and others skillfully arranged into a black background, usually of marble. The themes for design were primarily floral and they became miniature works of art. Another style of mosaics, roman or Byzantine, were made of tiny pieces of cut glass creating detailed landscapes, flowers and classical temples. Mosaics of superior quality were mounted in Solid Gold Frames; sometimes pinchbeck and sterling silver was used. Those pieces of a lesser quality were set in gold-filled or brass mountings. Mosaics were popular in England between 1820 and 1860. Those that were made in England were not as elaborate as the Italian mosaics, but still were very desirable. Even today, mosaics are produced in Italy for tourists.