Impulse was to say those GOP rocks would be hard .. then again there is no diamond there so igneous is out .. there would be little to no transformation .. http://en.wikipedia.org/wiki/Metamorphic_rock .. in any GOP bunch so that knocks metamorphic, so guess i'll settle for sedimentary .. yeah, sedimentary feels to fit best, even though it is softest a lotta dirty polluting stuff comes out of it (yup, shale), and those GOP are depositories of evermore discarded ideas ..