GENERAL GEOLOGY

Detailed explanation-1: -Tetragonal system possess one tetrad axis of four fold (1iv) symmetry. Zircon, rutile, scapolite, anatase and vesuvianite are a few common minerals that crystallise in the tetragonal system.

Detailed explanation-2: -The tetragonal unit cell is distinguished by an axis of fourfold symmetry, about which a rotation of the cell through an angle of 90° brings the atoms into coincidence with their initial positions. The elements boron and tin can crystallize in tetragonal form, as can some minerals such as zircon.

Detailed explanation-3: -There are six (6) elements of symmetry in crystals: a Center of Symmetry, an Axis of Symmetry, a Plane of Symmetry, an Axis of Rotatory Inversion, a Screw-axis of Symmetry, and a Glide-plane of Symmetry.

Detailed explanation-4: -Tetragonal system: Crystals of tetragonal system have three mutually perpendicular axes, two horizontal axes of equal length and one vertical axis, which can be either longer or shorter ( Fig. 1.1b). The axes are designated as a 1, a 2 and c. Tetragonal system possess one tetrad axis of four fold (1 iv ) symmetry.

Detailed explanation-5: -Axial Characters of Tetragonal System: The third crystallographic axes (vertical crystallographic axis) which is unequal (it may be bigger or smaller) therefore the symbol is a: a: c and the axial angle is ∠a ∠a ∠c = 90° [Fig.