Crystal Structure:
	Crystal structure is a unique arrangement of atoms in a crystal. A crystal structure is composed of a unit cell, a set of atoms arranged in a particular way; which is periodically repeated in three dimensions on a lattice.(1) To describe crystals, imaginary lines are used intersecting at 0 (the origin). These are specific to the various crystal systems, intersecting at given angles and being of given lengths specific to each crystal system.
	To discuss the six crystal systems, we have to describe what are called crystallographic axes. There are three axes: a, b, and c. The axes pass through the center of the crystal, and, by using them, we can describe the intersection of any given face with these three axes. (2)
	Crystal Structure determines the properties of the mineral. For example diamond and graphite are both made out of carbon. Diamonds are 10 on the Moh’s scale, conducts sound, is an insulator, and the best conductor of heat. Graphite is less than one on the Moh’s scale, conducts electricity and heat, and absorb light.All those differences are due to their crystal structure. Diamonds are arranged tetrahedrally, graphite is arranged in hexagonally in sheets.(3)
Website:  (1) https://www.sciencedaily.com/terms/crystal_structure.htm (2) http://www.mineralogy4kids.org/all-about-crystals/crystal-systems  
(3)https://www.scientificamerican.com/article/how-can-graphite-and-diam/
Isometric System
Characteristics of Isometric Crystals:
	•	Three crystallographic axes are all equal in length
	•	Intersect at right angles (90 degrees) to each other

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Hexagonal System
Characteristics of Hexagonal Crystals:
	•	Four crystallographic axes of equal length with angels of 120 degrees. The fourth axis is vertical.

Tetragonal System
Characteristics of Tetragonal Crystals:
	•	Three crystallographic axes that make right angles with each other
	•	Two horizontal axes of equal length, vertical axis is of a different length

Orthorhombic System
Characteristics of Orthorhombic Crystals:
	•	Three crystallographic axes of unequal length that make angles of 90 degrees with each other

Monoclinic System
Characteristics of Monoclinic Crystals:
	•	Three crystallographic axes of unequal lengths

Triclinic System
Characteristics of Triclinic Crystals:
	•	Three crystallographic axes are of unequal lengths that make oblique angles to each other