COLLECTION OF NATURAL CRYSTALS Crystal form is a valuable tool in the identification of minerals, but requires careful study. Perfect crystals are rare, but fragments and imperfect crystals will give basic information. The six crystal systems and examples are shown below.
CRYSTAL MINERAL SYSTEM FORM 1. Halite Isometric Cube 2. Magnetite Isometric Octahedron 3. Pyrite Isometric Cube 4. Apophyllite Tetragonal Prism & Pyramid 5. Beryl(Aquamarine) Hexagonal Prism 6. Apatite Hexagonal Prism & Dipyramid 7. Quartz Hexagonal Prism & Rhombohedron 8. Corundum Hexagonal Prism 9. Tourmaline Hexagonal Prism & Pinacoid 10. Aragonite Orthorhombic Prism & Pinacoid (Pseudo-hexagonal appearance is due to twinning!) 11. Topax Orthorhombic Prism & Pinacoid 12. Danburite Orthorhombic Prism & Pinacoid 13. Glauberite Monoclinic Prism & Pinacoid 14. Orthoclase Monoclinic Prism & Pinacoid 15. Amazonite Triclinic Prism & Pinacoid