Crystallography and Minerals Arranged by Crystal Form Amorphou s Isometr ic Tetrago nal Orthorhom bic Hexagon al Trigon al Monocli nic Triclinic 1. Crystal Groups and Classes - Crystallography groups are composed of 32 classes of symmetry derived from observations of the external crystal form. From these 32 classes, 230 space groups (see Crystallography 101 ) are distinguishable using x-ray analysis. For additional information on crystal systems, please review an excellent on-line treatment of this subject, the Introduction to Crystallography and Mineral Crystal Systems by Mike and Darcy System (1) Class Name (2) AXES Plan es Cent er Hermann- Maugin Symbols (3) 2- Fold 3- Fold 4- Fold 6- Fold Isometric Tetartoidal 3 4 - - - - 23 Diploidal 3 4 - - 3 yes 2/m 3 Hextetrahedral 3 4 - - 6 - 4 3m Gyroidal 6 4 3 - - - 432 Hexoctahedral 6 4 3 - 9 yes 4/m 3 2/m Tetragona l Disphenoidal 1 - - - - - 4 Pyramidal - - 1 - - - 4 Dipyramidal - - 1 - 1 yes 4/m Scalenohedral 3 - - - 2 - 4 2m
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Crystallography and Minerals Arranged by Crystal Form
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Crystallography and Minerals Arranged by Crystal Form
1. Crystal Groups and Classes - Crystallography groups are composed of 32 classes of symmetry derived from observations of the external crystal form. From these 32 classes, 230 space groups (see Crystallography 101) are distinguishable using x-ray analysis. For additional information on crystal systems, please review an excellent on-line treatment of this subject, the Introduction to Crystallography and Mineral Crystal Systems by Mike and Darcy