Igneous rocks are classified according to their texture and composition. Composition refers to both the types of minerals within a rock and the overall chemical makeup of the rock (the two are obviously related). Texture refers to the size and arrangement of the minerals or grains that make up a rock.
Pentatonix (or PTX) is an American a cappella group consisting of five vocalists originating from Arlington, Texas.entatonix began with three friends who grew up together and were schoolmates at Martin High School in Arlington, Texas: Kirstin Kirstie Maldonado (born May 16, 1992), Mitch Grassi (born July 24, 1992), and Scott Hoying (born September 17, 1991).
A pentagram (sometimes known as a pentalpha or pentangle or a star pentagon) is the shape of a five-pointed star drawn with five straight strokes.The word pentagram comes from the Greek word ÏÎµÎ½ÏÎ¬Î³ÏÎ±Î¼Î¼Î¿Î½ (pentagrammon), from ÏÎ­Î½ÏÎµ (pente), five + Î³ÏÎ±Î¼Î¼Î® (grammÄ), line.The word  pentacle  is sometimes used synonymously with pentagram. The word pentalpha is a learned modern (17th-century) revival of a post-classical Greek name of the shape.he pentagram is the simplest regular star polygon. The pentagram contains ten points (the five points of the star, and the five vertices of the inner pentagon) and fifteen line segments. It is represented by the Schlaefli schlÃ¤fli {symbol/5}. 2