MINERALOGY AND CRYSTALLOGRAPHY

MINERALOGY

Mineralogy is the study of minerals in the form of elements and compounds found in nature and is forming the solid parts of the universe. Mineralogy is not only limited to the materials of the earth's crust, but there are also from outside the earth, and based on geophysical measurements provide an indication of some of the properties of minerals contained under the crust.
Mineralogy is the branch of geology, because it is a rock-forming minerals of the earth's crust, Chemistry is also closely related to mineralogy, because the mineral is a chemical compound. The outer skin of the earth is called the crust, composed by solids that everyday we call rock. While the rocks are all kinds of materials that make up the earth's crust, and is an aggregate of minerals that have been hardened. Generally, a concoction some minerals rock.
Therefore mineralogy is the study of minerals, then we begin with a clear understanding of the mineral. To formulate a precise definition of the mineral in fact quite difficult. However, the mineral can be defined as follows: Minerals is a homogeneous solid objects found in nature, formed by inorganic, have a chemical composition on certain limits, and having the atoms are arranged in a regular
Mineral is a homogeneous solid body, it is stated that the mineral is composed of solid phase, only one kind of material that can not be broken down into compounds simpler by a physical process. With these requirements, then the liquid gas mapun excluding minerals.
Restrictions contained in nature is very necessary, because the chemical laboratory can be made a lot of minerals. For example, is the result of the evaporation of a solution of sodium chloride in the form of crystals that can not be distinguished from the mineral halite, also manufacture gemstone / accessories for commercial purposes, and so on.
Limitation that the mineral formed an organic-meaning that the mineral has a homogeneous solid objects generated instead of animals, plants and humans. However, do not eliminate the possibility of the presence of organic compounds as minerals. Many such substances, for example solid hydrocarbons, calcium oksulat been found in pet and coal; but is the result of burning natural distillation.
The requirement that the chemical composition of the mineral has a certain limit means minerals are chemical compounds, and chemical compounds that have a composition in certain limits are expressed in a formula either simple or complex. It depends on the number of existing elements and proportions combination.
Then another requirement is to have the atoms are arranged on a regular basis is a measure of the state of crystallization which can be seen in the picture outside. Position atoms in minerals according to certain rules, such as the mineral halite (NaCl) in which each atom of Na and Cl respectively surrounded by fields of eight by six Cl atoms and Na. While substances are not crystaling such as glass  nature, there is no regularity as mentioned above substances belonging to the amorphous substances.

Crystallography

Crystallography is the study of images of the crystal. Each type of mineral is not only composed of certain elements, but also has a particular form called crystal form. Crystalline form various patterns but always polieder or field a lot.
In the rare natural crystalline minerals ideal, the possibility dijumpa not in crystalline form but called crystal; For regular atomic arrangement. Proving it can be done with X-rays. Minerals that will be investigated given x-rays and minerals mounted behind the portrait sensitive paper. Thus the sheet of paper portrait will provide images. If the picture is regular and symmetric then the crystalline mineral, but if it does not say not so crystal.
Crystal is a solid object or substance that is homogeneous with the surface consists of flat areas formed by atoms or molecules are arranged regularly. Regularity properties of the composition is reflected by the outer face of the crystal that consists of flat areas. Complete crystal face is a polieder, and always limited by flat areas called fields crystal with a certain amount.
Minerals that crystallize bounded by areas together form the field much typical for a type of mineral. Regarding large crystals or crystal boundary wake there may be a triangle, rectangle, hexagon, and others-others are not so important. But most important is the angle field of two or polieder pivot angle of the crystal. Turns angle field two of each type of crystal is always fixed, this law we refer to as the Law of Steno (legal statutes two field angle). An example is the apatite crystals in which the angle between the x and m always at 130 ° 18 '. Two field angle measurement between x and m are using a goniometer or contact goniometer (reflectie goniometer).