rocks

rocks and the occasional mineral

BY DOMINICK HENRICKSEN

rocks

a rock is made up minerals depending on how fast is cools and where it is determines what type of rock and what type of minerals are in it

igneous rocks

An Igneous rock is formed through the cooling and solidification

below and on the earths surface

intrusive and extrusive intrusive are formed in side the earth and extrusive are formed on the earths surface

sedimentary rocks

are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water

inorganic, organic and chemically formed

metamorphic

Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form".[1] The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure (1500 bars),[2] causing profound physical and/or chemical change. The protolith may be sedimentary rock, igneous rock or another older metamorphic rock

pegmatite

A pegmatite is a intrusive igneous rock composed of interlocking phaneritic crystals usually larger than 2.5 cm in size such rocks are referred to as pegmatitic. Most pegmatites are composed of quartz, feldspar and mica, having a similar basic composition asgranite. Rarer intermediate composition and mafic pegmatites containing amphibole, Ca-plagioclase feldspar, pyroxene, feldspathoids and other unusual minerals are known, found in recrystallised zones and apophyses associated with large layered intrusions

breccia

Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix,[1] that can be either similar to or different from the composition of the fragments.

The word has its origins from Italian language, and in that language indicates either loose gravel or stone made by cemented gravel. A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia,tectonic breccia, igneous breccia, impact breccia and hydrothermal breccia.

phyllite

Phyllite is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.[1] It is primarily composed of quartz, sericite mica, and chlorite.[2]

Phyllite has fine-grained mica flakes in a preferred orientation, whereas slate has extremely fine clay flakes that achieve a preferred orientation, and schist has large flakes in a preferred orientation.[1] Among foliated metamorphic rocks, it represents a gradation in the degree of metamorphism between slate and schist