Petrology Petrology Petrology (from the Greek πέτρος, "pétros", "rock" and λόγος, "lógos", "subject matter", see -logy) is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together because they both contain heavy use of chemistry, chemical methods, and phase diagrams. Sedimentary petrology is, on the other hand, commonly taught together with stratigraphy because it deals with the processes that form sedimentary rock. Lithology was once approximately synonymous with petrography, but in current usage, lithology focuses on macroscopic hand-sample or outcrop-scale
What Is Art? in Tolstoy and his problems: essays. London: Grant Richards. pp. 66–101. Maude, Aylmer (1901b). “"What is Art?" - Tolstoy’s Theory of Art”, in Tolstoy and his problems: essays. London: Grant Richards. pp. 102–127. Noyes, George (1918). Tolstoy. London: Duffield. Pevear, Richard (1995). "Preface" in Tolstoy, Leo (1995 [1897]). "What is Art?" (Translated by Richard Pevear and Larissa Volokhonsky). London: Penguin. Simmons, Ernest (1973). "What is Art?", in Tolstoy. London: Routledge and Kegan Paul. pp. 175–189. What Is Art? What is Art? ( "Chto takoye iskusstvo?") is a book by Leo Tolstoy. It was completed in Russian in 1897 but first