It has been observed that all the crystals of minerals and synthetic substances studied so far can be grouped, on the basis of A - Closed form, B - Open form symmetry, into 32 (Thirty two) classes. These are often called crystal classes. By definition, all crystals with an external form of the same symmetry make a crystal class. All [...]
In this article we will discuss about:- 1. Meaning of a Crystal 2. Elements of a Crystal 3. Crystallographic Axes 4. Parameters, Indices, Symbols 5. Forms. Meaning of a Crystal: A crystal may be defined as a solid polyhedral form of a substance bounded by smooth geometrical surfaces called faces. Crystals may be natural or synthetic. Natural crystals occurring in [...]
In this article we will discuss about:- 1. Meaning of Twinning in Crystals 2. Some Illustrations of Twinning in Crystals 3. Types 4. Laws. Meaning of Twinning in Crystals: Generally crystals grow from the melts as individual specimens, each having its own shape, form and crystallographic characteristic. Sometimes, however, two crystals of the same compound may be formed from the [...]