Opificio delle pietre dure, Restoration institute and museum in Florence, Italy

The Opificio delle pietre dure is a public institute of the Italian Ministry of Culture in Florence, dedicated to art restoration, maintenance and teaching. Its historic seat at Via degli Alfani 78 occupies part of the former monastery of San Niccolò di Cafaggio, suppressed in 1783. The institute is divided into three locations: Via Alfani (commesso and mosaic, stone materials, bronzes, goldwork, ceramics, plus the school, library and museum), the Fortezza da Basso (paintings, paper, textiles, wooden sculpture) and the Sala delle Bandiere in Palazzo Vecchio (tapestries).

Ferdinando I de' Medici founded the workshop in 1588 in the former monastery of San Niccolò di Cafaggio to train craftsmen for the inlaid marble Cappella dei Principi in San Lorenzo. It moved to Via degli Alfani in 1796. After production of commesso furnishings declined at the end of the 19th century, it turned to restoring earlier works. In 1975 it merged with Ugo Procacci's 1932 restoration laboratory, Italy's first modern one, into today's institute.

The museum in Via Alfani displays Medici-era cabinets, table tops and plates in commesso, plus a baroque fireplace covered in green malachite and stone copies of paintings. The technique, perfected here from Byzantine inlay, selects stones for colour, opacity, brilliance and grain; a famous view of Piazza della Signoria appears in stone.

The institute is split across three sites: the historic headquarters at Via degli Alfani 78 houses the museum, library, school and stone, bronze, ceramic and mosaic laboratories; painting, paper, textile and wooden sculpture restoration is at the Fortezza da Basso; tapestries are treated in the Sala delle Bandiere in Palazzo Vecchio. The Via degli Alfani building occupies part of the former San Niccolò di Cafaggio monastery, suppressed in 1783.

The museum holds a large baroque fireplace entirely covered in malachite, a bright green stone, alongside inlaid stone copies of paintings. Some display space is devoted to paesina, a stone quarried near Florence whose grain and colour form landscape scenes.