Minerals in rock sections

Lea McIlvaine Luquer's Minerals in Rock Sections is a compact yet rigorous manual of petrographic microscopy, designed to teach students how to identify minerals in thin rock sections through direct optical observation. Emphasizing practical method over abstract theory, the book guides readers through mineral recognition by color, cleavage, relief, extinction, and other microscopic properties central to late nineteenth- and early twentieth-century mineralogy. Its style is clear, systematic, and pedagogical, reflecting the period when laboratory instruction and the polarizing microscope were transforming geology into a more exact observational science. Luquer was an American geologist and educator deeply engaged with the teaching of mineralogy and petrography. His work emerged from the needs of technical and scientific schools, where students required concise, reliable instruction in laboratory techniques rather than purely descriptive geology. This educational orientation helps explain the book's practical arrangement: it is written by someone attentive not only to scientific accuracy but also to the difficulties beginners encounter when first learning microscopic mineral identification. This volume is especially recommended to historians of geology, students of petrography, and readers interested in the development of scientific pedagogy. It remains valuable as both an instructional aid and a document of how mineralogical expertise was taught in an era of expanding laboratory science.