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All precious and semi-precious stones of geological origin and composition fall into wide and varied groups of different minerals, and thus the mineral is known as a natural, solid, homogeneous substance, formed in an inorganic way by natural geological factors and has a crystalline and chemical composition specific. Here is a simplified example of minerals on the granite rocks, which constitute a high percentage of the continental crust rocks. Each of these grains represents a separate mineral that rock. Thus, some rocks consist of one mineral and others consist of more than one mineral.
Based on the foregoing, coal, oil, and everything that is of organic origin and composition are not considered minerals.

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Chemical composition of minerals

Minerals consist of elements united with each other in certain proportions. It is about An element found in nature only 8 elements make up 141 % of the components of the earth’s crust, These elements are:
Oxygen, sodium, potassium, silicon, aluminum, iron, calcium, magnesium.

Notice that

The element is the basic unit of matter that cannot be broken down into simpler forms by ordinary chemical processes.

Some minerals consist of only one element such as gold and silver. Others consist of two or more elements, such as quartz (SiO2) and olefin (Mg.Fe)2SiO4. In addition, 9 of the major minerals make up most of the rocks of the Earth’s crust from the total A known mineral on the surface of the earth’s crust, and these minerals are:

feldspar, quartz, pyroxene, amphibole, mica, clay minerals, olefin, Calcite, and dolomite.

Crystalline nature of minerals

A crystal can be defined as any substance whose atoms are arranged in a regular order. And all minerals consist of crystals, for example, halite mineral (NaCl) consists of a sodium ion Na + for each chlorine ion Cl-

Appearance of a crystalline metal – Physical properties of minerals

Physical properties of metals

(Although the chemical and crystalline composition can distinguish each mineral from the other, it is possible to identify minerals by a simple examination of their physical properties, and those properties are limited to:

1- Color

Color is a physical characteristic and is usually unreliable by itself. In distinguishing minerals as a result of changing the colors of some of them. As a general rule, minerals can be divided in terms of color into fixed-color minerals such as gold and silver, and color-changing minerals such as quartz and fluorite.

It is the color of metal powder and can be obtained by rubbing the metal. The color of the mineral and the color of its powder (scratched) may be the same or may differ. For example, pyrite is copper-yellow and has a black streak. Hematite is black and has a red scratch, and olivine is olive green and has a yellowish-white scratch.It is the ability of the mineral to transmit light, and minerals are divided in terms of transparency into three sections: 1- Translucent metals: They are minerals that allow all the light falling on them to pass through and things can be seen Through it like quartz.

2- Semi-transparent minerals: They are minerals that allow the passage of a large amount of water. From the light falling on it, such as orthoclases and opals. 3- Opaque minerals: , which are minerals that do not Allows light to pass through even through its thinner segments such as pyrite and garnet.

4- Luster

It is the ability of the mineral to reflect the light rays falling on it, and minerals are divided according to this property into two parts:


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