Pietra dura, meaning 'hard rocks' in Italian, is a technique requiring a high level of skill, whereby precious and semi-precious stones are cut, fitted and highly polished to form a pictorial mosaic usually for table tops and other furniture. The pietra dura technique was originally developed in ancient Roman times, but truly began to flourish in the Italian Renaissance period – particularly in Florence, where it was referred to as ‘painting in stone’. The style remained popular until well into the 19th Century, with pietra dura table tops being especially highly sought after as they usually provided the most impressive examples of the technique.