Regarding the causes of igneous rock diversity, the emphasis in both Basic Earth Science and Earth Science of high school sciences is on crystallization differentiation, which does not fully reflect the current knowledge of petrology. This makes it difficult to understand theories of other diagenetic processes closely related to actual volcanoes. In addition, to cultivate the “way of seeing and thinking” in science, it is necessary to use scientific methods of inquiry, such as comparing and relating by utilizing the acquired knowledge. In this study, the Abu Monogenetic Volcanoes, formed by magma mixing, were examined for their usefulness as learning materials. The aim is to develop a learning program to understand the formation process of igneous rocks in an exploratory manner. Consequently, it was confirmed that the results of basic learning activities, such as observation of volcanic rocks and their thin sections, can be discussed in relation to rock formation as in previous studies using Usu Volcanoes. This suggests that developing a learning program using volcanic ejecta, the formation process clarified by petrological studies, helps solve problems related to understanding igneous rock diversity in school education.