The natural curiosity and interest students have for rocks will open the doors for learning about basic aspects of geology while learning skills of observation, recording data, and making inferences. Rocks are used in many different ways. The use is generally determined by the characteristics of the rock. It wouldn't make much sense to construct a counter- top out of soft limestone, for instance, or to write on a chalkboard with a chunk of marble. Different rocks are used for different purposes according to the characteristics and qualities of the rock.
Limestone is used in making cement and gypsum is used in making sheet rock.
The mineral graphite is used in making lead pencils. Some hard rocks, such as granite and marble, are cut, polished, and used in the construction of buildings and monuments. There are many opportunities to discover the uses of rocks by making observations around the home, school, and the community. Rocks are often classified by how they were formed. Three major categories are igneous , sedimentary , and metamorphic.