CRYSTALS DEFINITION & EXTERNAL CHARACTERS


  Crystals are bodies bounded by surface usually flat, which is an reflection of internal atomic arrangement. Crystals are formed by the solidification of minerals from the gaseous or liquid state or from solutions by a process known as crystallization.

Face - The plane surface or faces are the most obvious feature of crystals are parallel to net-planes in the crystal structure.

Forms - A crystal is made up entirely of like faces is termed a simple form. A crystal which consist of two or more simple forms is called combination.

Edge - An edge is formed by the intersection of two faces.

Solid Angles - A solid angle is formed by the intersection of three or more faces.

Interfacial angle - The angle between any two faces of a crystal is termed the interfacial angle.