Introduction
Minerals are naturally occurring inorganic solid substances made up of atoms, molecules, or ions held together by chemical anchors and organized into regular three-dimensional crystal structures. While many are known and identified, there are still unknown minerals or undiscovered compounds that may exist. This article will focus on the structural aspects of minerals, the various types of crystal structures, and the principles that govern those structures.
Crystal Structures
A crystal is a solid formation of atoms that have been arranged in a particular repetitive arrangement. The three-dimensional arrangement of the atoms creates a regular crystal lattice, which is a repeating geometric pattern. Minerals can display different types of crystal structures depending on their compositions and ingredients.
Cubic Structure
In a cubic structure, all the atoms of the crystal are arranged in an orderly, cube-like pattern. This cubic structure is often a repeating network of eight atoms that form the corners of a cube, known as a unit cell. The cube-shaped arrangement of atoms creates a regular repeating pattern of eight atoms, which can be seen in crystals, such as pyrite, fluorite, and alloys.
Hexagonal Structure
The hexagonal structure is comprised of two or more crystal lattices in a hexagonal arrangement. This type of lattice is characterized by six-sided, repeating patterns of atoms, which are arranged in three-dimensional shapes like pyramids or cylinders. This type of crystal is common in metallic elements such as gold, silver, and platinum, minerals like biotite mica, and tourmaline, and boron nitride.
Trigonal Structure
The trigonal structure consists of a repeated triangular pattern of atoms that creates an angled crystal lattice. This type of crystal is commonly found in minerals such as quartz, carborundum, and topaz. This structure is also found in many polymers, such as polyvinyl chloride and polystyrene.
Tetragonal Structure
The tetragonal structure is similar to the cubic structure, but the unit cell is elongated in one direction. This type of crystal can be found in nature when the atoms of a cubic crystal lattice become bigger or in a compound that doesn’t have all the same atoms. Minerals such as albite, zircon, and perovskite are all examples of tetragonal crystals.
Orthorhombic Structure
The orthorhombic structure is an arrangement of crystal lattices in which the unit cell is elongated in two directions. This type of lattice is often found in colloidal minerals like gypsum, opal, and diamond.
Monoclinic Structure
The monoclinic structure is characterized by a non-parallel arrangement of two or more crystal lattices in an angled pattern. This type of crystal lattice is found in minerals such as lazurite, talc, and graphite.
Conclusion
Minerals can have a variety of different crystal structures, ranging from cubic and hexagonal to trigonal, tetragonal, orthorhombic, and monoclinic. The various lattices are determined by the arrangement of atoms in each mineral and can vary greatly in size and shape. The organization of these atoms into a repeating pattern gives each mineral its unique properties. Understanding the crystal structures of minerals is essential for scientists trying to identify and study unknown minerals.
