Igneous rocks are typically named based on mineralogy.  You look at a fresh rock surface and the minerals seen are common ones that can be readily identified and the relative proportions are estimated. Some buildings, especially those constructed from cobbles and boulders done as decorative masonry work, are great places to practice rock identification.  The MTU Credit Union is an excellent example of this.  The building has very fresh surfaces of many different kinds of igneous rocks which can be used as rock ID locations.  It is possible to make a quiz of the building surface. The office does not need to be open because the fresh rock surfaces are abundant on the outdoor as well as indoor parts of the building.  Such buildings can be found in many communities.