what is a rock?
In geology, rock or stone is a naturally occurring solid aggregate of one or more minerals or mineraloids.For example, the common rock granite is a combination of the quartz, feldspar and biotite minerals. The Earth's outer solid layer, the lithosphere, is made of rock.he types and abundance of minerals in a rock are determined by the manner in which the rock was formed. Many rocks contain silica (SiO 2); a compound of silicon and oxygen that forms 74.3% of the Earth's crust. This material forms crystals with other compounds in the rock.
Musically, rock has centered on the electric guitar, usually as part of a rock group with electric bass guitar and drums. Typically, rock is song-based music usually with a 4/4 time signature using a verse-chorus form, but the genre has become extremely diverse.Like pop music, lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political in emphasis.ooted in garage rock and other forms of what is now known as protopunk music, punk rock bands eschewed the perceived excesses of mainstream 1970s rock. They created fast, hard-edged music, typically with short songs, stripped-down instrumentation, and often political, anti-establishment lyrics.