Mineralogy Certification Course
Crystal System Structure Chart
| Structure | Crystal axes and Angles | Optic Character | Refractive Indexes | Optic Sign | Pleochroism | Examples |
| Amorphous | No orderNo axes | IsotropicSingly refractive | 1 RI | None | None | Opal, Amber, Glass, Plastic |
| Isometric | 1 axis lengthAll at 90° | IsotropicSingly refractive | 1 RI | None | None | Diamond, Spinel, Garnet |
| Tetragonal | 2 axis lengths All at 90° | AnisotropicDoubly refractive | 2 RI's | Uniaxial | May be dichroic | Zircon |
| Hexagonal | 2 axis lengths | AnisotropicDoubly refractive | 2 RI's | Uniaxial | May be dichroic | Quartz, Beryl, Apatite, Corundum, Tourmaline |
| Orthorhombic | 3 axis lengthsAll at 90° | AnisotropicDoubly refractive | 3 RI's | Biaxial | May be trichroic | Topaz, Zoisite, Peridot |
| Monoclinic | 3 axis lengths 2 axes at 90°; 1 oblique | AnisotropicDoubly refractive | 3 RI's | Biaxial | May be trichroic | Orthoclase, Spodumene |
| Triclinic | 3 axis lengths all axes oblique | AnisotropicDoubly refractive | 3 RI's | Biaxial | May be trichroic | Labradorite, Axenite |
GEM STRUCTURE CHART
Purchase Mineralogy Certification Course
This course is for anyone interested in the study of minerals, their properties, and their significance in Earth's systems. It covers fundamental concepts such as the mineral life cycle, the chemical and physical properties, crystallography, mineral classification, and testing. To pass this course, you must successfully complete a written test and a practical exam, which involves the correct identification of 5 minerals.
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