 September 2021 - Global Epidemic Observational Studies Organization

# Month: September 2021

## Tetragonal Crystal System

In our previous post, we discussed in detail the classes and forms of Cubic/ Isometric Crystal System, which is a very common type of crystal and includes hundreds of minerals in this system. This post is about the ”tetragonal crystal system”. The tetragonal crystal system is another important system. Zircon, Cassiterite, and Rutile are the

## Cubic/ Isometric Crystal System

Some common minerals like galena, garnet, fluorite, and magnetite are found in cubic or isometric crystal systems. The crystals of this group have three mutually perpendicular axes of equal lengths. These axes are interchangeable and are designated as a1, a2, and a3. The axes of cubic/isometric crystal systems are as follows. Classes of Isometric System

## Six types of Crystal Systems

There are hundreds of minerals on the earth, which are found in different crystal forms. These crystal forms are grouped into six major crystal forms. These crystal forms are as follows. (1). Cubic or Isometric Crystal System: The crystals belonging to this system have three mutually perpendicular axes of equal lengths. These axes are designated

## Symmetry elements of crystals

All kinds of crystals have a symmetrical form, which is known as the symmetric characteristic of the crystals. The symmetry elements are used as parameters to describe this symmetry. Three elements of symmetry can be recognized in a crystal. These are (i) plane of symmetry, (ii) axis of symmetry, and (iii) center of symmetry. (1).

## Interfacial Angle of Crystals

Interfacial angle is the angle between adjacent faces of the crystal lattice. Because crystal faces have a direct relationship to the internal structure, it follows that the faces have a definite relationship to each other. This relationship is expressed ”law of constancy of interfacial angles”, which states that ”the interfacial angles between corresponding faces are

## Crystallographic axes

Crystallographic axes are the imaginary lines, which we can draw within the crystal lattice. In order to describe the faces and symmetry of crystals, a set of three or four reference axes are established.  These imaginary reference axes are established. These imaginary reference lines are called ”crystallographic axes” and are generally taken parallel to the