A new mortar from a strange ancient mortar

During the restoration of Perseus, a sculptural complex realized by G. B. Pieratti in the XVII century sited in Boboli Garden (Florence), an ancient mortar used as glue of iron pivots with very particular characteristics was found. Indeed this mortar was made of a magnesium hydroxide based binder (brucite) and barite (barium sulphate) as aggregate. This mortar still show excellent conservation conditions. The aim of this work was trying to reproduce the ancient mortar according to the analytical data about its composition.