Small flecks of dacite rock rained down onto the tarp beneath his feet as he laboriously shaped the slab into arrowheads, knives and other primitive tools. They had all come to watch Shea demonstrate knapping, the shaping of rock through reduction and fracturing to create tools.Shea said that he often uses rocks at stone age such as dacite, quartzite and sandstone, which are found in abundance in Stony Brook. However, he imports them from Oregon because according to him, "the quality of the rocks is better."