This is a measurement of abiethic acid with a melting temperature of +143 ° C., obtained by O. O. Koshelev in the laboratory of Prof. Chugaev from a solution in ethyl alcohol in the form of colorless transparent crystals. The crystals belong to the rhombic system of the gynohexagonal type and have a lamellar appearance with the most strongly developed face (0101) and are almost always elongated in one of two directions: either along the [1000] axis or along the [0121] axis. On all observed crystals, the (0101) faces were strongly and completely irregularly curved. See the figure and measurement results in the article.
