Abstract This paper reports the research results over several years on Piperno, the most important ornamental architectural stone of Naples. Particular attention is paid to the rediscovery of the old exploitation sites of this rock and to the survey of the last underground quarry site, still accessible, at the base of the Camaldoli Hill (western Naples) at Pianura. The conservation state was assessed by means of specific surveys in view of possible future utilization. At present, the re-opening of abandoned quarries is not possible owing to unsafe site conditions. The cultural relevance of the Pianura quarry site could suggest its possible restoration as a museum of mining and a centre for teaching the working of ornamental stone within the Campania Region.