Hamstone is the colloquial name given to stone from Ham Hill, Somerset, England. Ham Hill stone is a Jurassic limestone from the Toarcian, or Upper Lias, stage. It is a well cemented medium to coarse grained limestone characterised by its honey-gold colour and marked bedding planes. The stone contains thin beds of less well cemented material and some small clay inclusions. These areas weather differentially to give weathered hamstone its characteristic furrowed appearance.
Ham Hill stone is quarried in two areas on the top of Ham Hill. The North quarry extracts stone from just beneath the surface, whilst the stone extracted from the South Quarry is found some 20-30 metres below the surface.
The town of South Petherton is built largely of hamstone.