Your rock is a sandstone.  Geologists classify sandstones based on the mineralogy of the sand grains that make up the rock. Use your hand lens and look closely at your rock.  Quartz does not exhibit any cleavage, so it will likely be fairly well rounded.  The grains often look like little clear or white spherical balls when viewed through your hand lens. Feldspar on the other hand does have cleavage. So when it weathers, it often breaks along the cleavage planes yielding small planer surfaces on the grains. You may be able to identify very small flat surfaces on the grains when you examine it with your hand lens. Feldspar may also be darker and sometimes pinkish in color.