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 was used in ancient times as a Christian symbol for the five senses, or of the five wounds of Christ. A Christian use of the pentangle occurs in the 14th-century English poem Sir Gawain and the Green Knight, in which the symbol decorates the shield of the hero, Gawain.