Material properties of diamond these are known as ballas and are important to industry as they lack the cleavage planes of single-crystal diamond. Carbonado is a similar opaque microcrystalline form which occurs in shapeless masses. Like ballas diamond, carbonado lacks cleavage planes and its specific gravity varies widely from 2.9 to 3.5. Bort diamonds, found in Brazil, Venezuela, and Guyana, are the most common type of industrial-grade diamond. They are also polycrystalline and often poorly crystallized; they are translucent and cleave easily. Because of its great hardness and strong molecular bonding, a cut diamond's facets and facet edges appear the flattest and sharpest. A
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