# Difference between revisions of "Crystal Systems"

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! Examples | ! Examples | ||

|- | |- | ||

− | | '''Cubic''' <br> | + | | '''Cubic''' <br /> |

− | The cube is composed of 6 square faces<br> | + | The cube is composed of 6 square faces<br /> |

− | at 90° angles to each other. Each<br> | + | at 90° angles to each other. Each<br /> |

− | face intersects one of the crystallographic<br> | + | face intersects one of the crystallographic<br /> |

− | axes and is parallel to the other two.<br> | + | axes and is parallel to the other two.<br /> |

| [[image:cubic.jpg]] | | [[image:cubic.jpg]] | ||

|[[Diamond]] <br /> | |[[Diamond]] <br /> | ||

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| '''Tetragonal''' <br /> | | '''Tetragonal''' <br /> | ||

− | The tetragonal system also has three axes<br> | + | The tetragonal system also has three axes<br /> |

− | that all meet at 90°. It differs from the<br> | + | that all meet at 90°. It differs from the<br /> |

− | isometric system in that the C axis is longer<br> | + | isometric system in that the C axis is longer or<br /> |

− | than the A | + | shorter than the A axes,<br /> |

− | + | which are the same length.<br /> | |

| [[image:tetragonal.jpg]] | | [[image:tetragonal.jpg]] | ||

|[[Zircon]] | |[[Zircon]] | ||

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the hexagonal and the trigonal, based on their external<br> | the hexagonal and the trigonal, based on their external<br> | ||

appearance (see following). | appearance (see following). | ||

− | |[[image: | + | |[[image:hexagonal.jpg]] |

|[[Aquamarine]]<br /> | |[[Aquamarine]]<br /> | ||

[[Beryl]] <br /> | [[Beryl]] <br /> | ||

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[[Heliodor]]<br /> | [[Heliodor]]<br /> | ||

[[Morganite]]<br /> | [[Morganite]]<br /> | ||

+ | [[Apatite]] | ||

|- | |- | ||

| '''Trigonal'''<br /> | | '''Trigonal'''<br /> | ||

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therefore some gem references will list these as<br /> | therefore some gem references will list these as<br /> | ||

hexagonal. | hexagonal. | ||

− | | [[image: | + | | [[image:trigonal.jpg]] |

|[[Amethyst]]<br /> | |[[Amethyst]]<br /> | ||

[[Benitoite]]<br /> | [[Benitoite]]<br /> | ||

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In this system, there are three axes all of which<br /> | In this system, there are three axes all of which<br /> | ||

meet at 90° to each other. However, all the axes<br /> | meet at 90° to each other. However, all the axes<br /> | ||

− | are | + | are of different length. |

− | |[[image: | + | |[[image:Orthorhombic.jpg]] |

|[[Alexandrite]]<br /> | |[[Alexandrite]]<br /> | ||

[[Andalusite]]<br /> | [[Andalusite]]<br /> | ||

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the axes are different lengths. The A axis is inclined<br /> | the axes are different lengths. The A axis is inclined<br /> | ||

to the C axis. The B axis is at 90° to them. <br /> | to the C axis. The B axis is at 90° to them. <br /> | ||

− | |[[image: | + | |

+ | You can imagine this as a matchbox that slants to one side. | ||

+ | |[[image:monoclinic.jpg]] | ||

|[[Azurite]]<br /> | |[[Azurite]]<br /> | ||

[[Diopside]] <br /> | [[Diopside]] <br /> | ||

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In this system all the axes are different <br /> | In this system all the axes are different <br /> | ||

lengths and none of them meet at 90°. | lengths and none of them meet at 90°. | ||

− | | [[image: | + | |

+ | You can imagine this as a matchbox which slants to two sides. | ||

+ | | [[image:triclinic.jpg]] | ||

|[[Turquoise]] | |[[Turquoise]] | ||

|} | |} | ||

+ | <br > | ||

+ | '''Next:[[Form| Form]]''' | ||

+ | <br /><br /> | ||

+ | '''[[Table_Of_Contents| Return to the Table of Contents]]''' |

## Latest revision as of 10:42, 13 December 2012

Crystal System | Diagram | Examples |
---|---|---|

Cubic The cube is composed of 6 square faces |
Diamond | |

Tetragonal The tetragonal system also has three axes |
Zircon | |

Hexagonal
In the hexagonal system, we have an additional axis, |
Aquamarine | |

TrigonalThe trigonal system is a subsystem of the |
Amethyst | |

OrthorhombicIn this system, there are three axes all of which |
Alexandrite Andalusite | |

MonoclinicThe above crystal systems all have axes sides You can imagine this as a matchbox that slants to one side. |
Azurite | |

TriclinicIn this system all the axes are different You can imagine this as a matchbox which slants to two sides. |
Turquoise |