What is "hamstone"

Hamstone is the colloquial name given to stone from Ham Hill, Somerset, England. Hamstone 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.