A rock cycle

A rock cycle is a process that is exhibited by the formation, breakdown, and reformation of a rock. It is also the process of transformation of rocks from one state to another in a cyclic manner. The three main groups of rocks are igneous, sedimentary, and metamorphic (Fossen, 2016). These rocks are connected by the processes they undergo over time. Rocks usually change form from one group to another, forming a cycle. The cycle begins with granite, which is an example of igneous rock that forms from the crystallization of magma.

Rocks can start as magma. Magma is formed when rocks partially melt as a result of disturbance or pressure from the upper mantle. Magma erupts, cools and crystallizes to form igneous rocks at the surface. Igneous rocks can either be intrusive or extrusive (Fossen, 2016). In an extrusive case, the rock will experience weathering and decomposition due to the natural environment forming some particles. The particles that are left after weathering and disintegration are known as sediments. 

The sediments can be deposited from different places such as oceans. The sediments then go through a process of lithification where they are compacted and pressed to form sedimentary rocks. The sedimentary rocks are then subjected to heat and pressure, forming metamorphic rocks (Fossen, 2016).  As the rock continues to sink deeper below the crust, the heat melts it to magma completing the cycle which can start later. 

Question 2

Minerals are elements that form as a result of a geological process. There are distinct characteristics that explicitly defines a mineral. The first characteristic is that minerals occur naturally because they exist as a result of a geological procedure (Fossen, 2016). Minerals are inorganic in nature because they are naturally found from the ground. The third characteristic is that minerals are solid and hard. Minerals are solid because of their rigid structure.

Another characteristic is that minerals usually exhibit a crystalline structure because of their atomic and molecular arrangement (Fossen, 2016). The last characteristic of minerals is that they tend to break along lines, creating a cleavage when sharply hit by an object. This character can make one be able to identify if a substance is a mineral or not. Window glass exhibits some characteristics of a mineral like being inorganic but it does not have a proper arrangement of atoms which disqualifies it. Glass has a definable chemical makeup and can be produced naturally by volcanoes. 

Synthetic opal is disqualified in the list of minerals because it is artificially made and does not occur naturally. Wood is also not a mineral since it is an organic material. Amber exhibits a mineral characteristic because it exists from fossilized resins that originates from historic trees. However, it is not a mineral because its existence makes it an organic substance hence disqualifying it from being a mineral.

Granite is formed from a composition of two matters, namely; Quartz and feldspars. The composition of the two matters makes granite have a defined chemical composition; therefore, it can be considered as a mineral. Water is not a mineral because it exists in its normal state. Ice is considered a mineral because it is solid and has a fixed chemical composition. Emerald is a mineral because it naturally occurs on its own and inorganic in nature.

Reference

Fossen, H. (2016). Structural geology. Cambridge University Press.

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