Types of Crystal Structure and How Crystals are formed? Crystal and Mineral Identification - Folkmarketgems

Types of Crystal Structure and How Crystals are formed? Crystal and Mineral Identification

What are types of Crystal Structure and how crystals are formed?

Do you want to learn about Crystal Structure are formed in waht way? How one can define crystal definition? The answer of this question will definitely help you understanding the identification of the minerals and gemstones. Every gemstones and mineral have a specific form of crystal structure. That specific crystal structure has a a specific arrangements of ions, molecules, atoms inside. This is the arrangements of atoms and specific shape, arrangement of ions and molecules which gives a particle structure to any gemstone and mineral. 

The researchers have done lot of work on collecting data to analyse the crystal structures of minerals. Those crystal structures of gemstones and minerals have been defined by the scientists and the researchers as following:-

  1. Crystals by Shape or grouped by Lattices
  2. Recognition of crystals by properties

Let us first discuss crystals grouped by Lattices.

1-Shape of Crystals or Crystals Grouped by Lattices

In Lattices group of crystals, in order to identify the crystals , the researchers have defined 7 different crystalline  structures mentioned below

  1. Tetragonal: This type of crystal structure is similar to cubic structure however they are longer on axis than the other. The tetragonal system has 3 axes which all meet at 90 degrees. Though being square base in its crystal structure, it's height will be longer than the axis. These Crystals form double pyramids and prisms.
    TetragonalTetragonal crystal structure
  2. Cubic or Isometric: They have sometime octahedrons having 8 faces and some times dodecahedrons having 10 faces. Examples are flourite, pyrite. Checkout Cubic crystal structure stones 
     Cubic crystal structure
  3. Orthorhombic: They are like Tetragonal with one difference, they are not square in cross section. Such crystals form rhombic prisms and dipyramid. Aragonite , topaz is example. 
    Orthorhombic crystal structure
  4. Hexagonal: When These crystals will have 6 sided prism and hexagon. Beryl is an example. Other examples are Emeralds.  Check out here Hexgonal structured crystals or gemstones
    Hexagonal Crystal Structure Hexagonal Emerald
  5. Trigonal: These have single 3 gold axis of rotation instead 6 fold like hexagonal division.abhurite, alpha-quartz is an example. Trigonal crystal structure Quartz 
  6. Triclinic: These crystals do not come in a symmetrical form which leads t strangers shaed. Axinite, kynite is an example. Triclinic crystal structure Kynite
  7. Monoclinic: Like These crystals usually work prisms and double pyramids. Examples are gypsum, orthoclase, muscovite, clinoamphibole, clinopyroxene, jadeite, azurite, and spodumene Monoclinic crystal structures 

Crystals Grouped by Properties

There are 4 different crystal categories according to their chemical and physical propertes.

  1. Covalent Crystals: A covalent crystal will have strong covalent bond between all atoms. Covalent crystal can be called as a big molecule. Such Crystals are melt on very ugh melting points. Examples are diamond, zircon. 
  1. Metallic Crystals: This is very interesting. In the crystal structure,  metal atoms of crystals lays on lattice sites.outer electrons flour outside the latice. Metallic crystals are dense and also having high melting points.  Like Bismuth Metallic crystals Metallic crystals structure
  2. Ionic Crystals: The atoms of ionic crystals are bound together by ionic bonds. Such crystals are very hard. They also have a high melting points. Ionic crystal structure
  3. Molecular Crystals: These crystals are held together by non covalent interactions like hydrogen bonding. recognizable molecules within their structures. Such crystals are usually soft and having low melting point. Table sugar is an example. 
These data is based on researches made by researchers. There is no definite rule to define crystals. As new Gemstones and minerals appear in different regions with more complex crystal structure. Than new rules are to be decided. However already researched can help us in recognizing gems and minerals.

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