Feltsitic

Feltsitic is a term used in geology to describe a type of igneous rock that is characterized by the presence of felsic minerals. Felsic minerals are light-colored silicates that are rich in silica, aluminum, potassium, and sodium. Common felsic minerals include quartz, feldspar, and mica. Rocks containing a high proportion of these minerals are typically light in color, often white, pink, or light gray.

Examples of felsic rocks include granite, rhyolite, and syenite. Granite is a coarse-grained intrusive rock, meaning it formed from magma that cooled slowly beneath the Earth's surface. Rhyolite is its fine-grained extrusive equivalent, formed from lava that cooled quickly on the surface. Syenite is similar to granite but contains less quartz.

The composition of felsic rocks indicates that they formed from magmas with a high silica content. These magmas are generally more viscous and cooler than mafic magmas. Felsitic rocks are common in continental crust and are often found in areas of past or present volcanic activity or in large mountain ranges. Their texture can vary significantly depending on the cooling rate of the magma or lava from which they formed, ranging from large, interlocking crystals in intrusive rocks to very fine grains or even glassy textures in extrusive rocks.