Rift, grain and hardway

Terms common in quarrying, indicating the three orthogonal directions of preferred splitting within massive, quartz-bearing, igneous rock. The rift is the direction of easiest splitting and is usually horizontal or nearly so. The grain, usually perpendicular to the rift, is the direction of next easiest splitting. The hardway (or headgrain) is the plane of most difficult splitting among the three directions. In hard rock tunnelling, if the hardway direction is normal to tunnel advance, considerable powder is required for removal.