An unusual mortar with a magnesium binder in the Perseus of Giovan Battista Pieratti in Boboli Gardens (Florence)

摘要

The restoration of Perseus Boboli Gardens (Florence, Italy), a sculptural complex realized by Giovan Battista Pieratti in the 30~(th) of the XVII century mostly as reuse and reinterpretation of fragments of ancient Roman sculptures, offered the opportunity to face the problem of the structural consolidation of a fragmented sculpture. During disassembly of this sculptural complex it was possible to observe an overlapping of techniques and materials that covers more than three and a half centuries, from the first half of the XVII century until the 80~s of the XX century. One of the materials used as glue of the pivots showed an unusual composition, characterized by a magnesium hydroxide based binder (brucite) and brucite and barite as aggregate. It is probably an old mortar still in excellent conservation conditions.