The widespread building activities in Israel during the 9-10th centuries B. C. required enormous quantities of ashlar stones. The particular quarries used have been identified from the geological nature of the stone used and the stratigraphy relating quarry and site of use. The stages in quarrying technique can be reconstructed -- the cutting of successive steps into exposed rock. Geological study shows that for major IA sites the builders used only nari limestone for monumental masonry. It was preferred because it was less friable than chalk, not as difficult to work as harder limestones and hence suitable to the capabilities of the IA stonemasons. In contrast, the BA workers preferred harder limestone and even basalt; Hellenistic and Byzantine workers also used a range of the harder limestones. -- AATA