<div style="position: absolute; left: 49px; top: 16px; padding: 0; background-color: #60e0ff; opacity: 0.3; width:172px; height:197px;"> **Silicic** is an adjective to describe [magma](https://bliptext.com/articles/magma) or [igneous](https://bliptext.com/articles/igneous) rock rich in [silica](https://bliptext.com/articles/silica). The amount of silica that constitutes a silicic rock is usually defined as at least 63 percent. [Granite](https://bliptext.com/articles/granite) and [rhyolite](https://bliptext.com/articles/rhyolite) are the most common silicic [rocks](https://bliptext.com/articles/rock-geology). Silicic is the group of silicate magmas which will eventually crystallise a relatively small proportion of ferromagnesian [silicates](https://bliptext.com/articles/silicate), such as [amphibole](https://bliptext.com/articles/amphibole), [pyroxene](https://bliptext.com/articles/pyroxene), and [biotite](https://bliptext.com/articles/biotite). The main constituents of a silicic rock will be minerals rich in silica-minerals, like silicic [feldspar](https://bliptext.com/articles/feldspar) or even free silica as [quartz](https://bliptext.com/articles/quartz). These are just part of all the other [silicate minerals](https://bliptext.com/articles/silicate-mineral) that make up 90% of the earth's [crust](https://bliptext.com/articles/crust-geology). This broad classification is refined in practice based on more detained compositional studies where ever possible in the science of [mineralology](https://bliptext.com/articles/mineralology). # [Silicic refers to the uncoloured igneous rocks to the right in this TAS classification (Na2O + K2O) versus silica (SiO2) | upload.wikimedia.org/wikipedia/commons/4/43/Petrology///Igneous.svg] # [In this top of a QAPF diagram for classification of plutonic rocks, silicic rocks are uncoloured at the top of the figure (Q is for Quartz which is pure silica) | upload.wikimedia.org/wikipedia/commons/1/14/Streckeisen///for///intrusive///quartz///igneous///rocks.svg]

Example

The "Shammar group" is a silicic and volcaniclastic sequence in northwestern Saudi Arabia.