What is the monoclinic crystal system in mineralogy ?
Monoclinic crystal system : definition
The monoclinic system is a crystalline system whose unit cell is an oblique prism with four parallelogrammatic side faces equal to 2 to 2, and two rectangular bases. The three axes are of different lengths and only two angles are equal to 90° ; the third is variable and characteristic of the mineral species. This system has 3 crystalline classes.
This system include about 21% of mineral species, the most common being micas, the majority of amphiboles and pyroxenes, gypsum, orthoclase, talc, chlorites, etc...
Certain monoclinic cells are said to be pseudocubic, pseudoquadratic, pseudo-orthorhombic or pseudohexagonal, when the cell parameters of a given monoclinic crystal approach those of these crystalline systems.
This system include about 21% of mineral species, the most common being micas, the majority of amphiboles and pyroxenes, gypsum, orthoclase, talc, chlorites, etc...
Certain monoclinic cells are said to be pseudocubic, pseudoquadratic, pseudo-orthorhombic or pseudohexagonal, when the cell parameters of a given monoclinic crystal approach those of these crystalline systems.