
Continue Reading about Gemstone Properties Gemstone Cleavage Gemstone Clarity Gemstone Form Gemstone Scarcity Gemstone Color Specific Gravity Luster 
Hexagonal system
Three of the four axes have the same length and are located in one plane. These axes intersect each other at an angle of 120 degree. Typical crystal shapes are hexagonal prisms and pyramids, as well as twelvesided pyramids and double pyramids.
Trigonal system
Axes and the angles are similar to the hexagonal system. The difference is one of symmetry. In the case of hexagonal system, the cross section of the prism base is six sided; in trigonal system it is threesided. Typical crystal forms of the trigonal system are threesided prisms and pyramids, rhombohedra, and scalenohedra.
Orthorhombic system
Three axes of different lengths are at right angles to each other. Typical crystal shapes are pinacoids, rhombic prisms, Pyramids, and Double pyramids.
Monoclinic system
The three axes are each of different length, two are at right angles to each other and the third one is inclined. Gemstones from monoclinic system form basic shapes of Basal pinacoids and prisms with inclined end faces.
Triclinic System
All three axes are of different lengths and inclined to each other. Typical crystal forms are paired faces.
Below is the selected gemstone categorized by crystal system
cubic hexagonal  tetragonal  trigonal  orthorhombic  monoclinic  triclinic  Amorphous 

Almandine  Anatase  Agate  Adamite  Aegerineaugite  Amazonite  Amber 
Analcime  Apophyllite  Amethyst  Alexandrite  Azurite  Amblygonite  Chrysocolla 
Andradite  Boleite  Aventurine  Andalusite  Barytocalcite  Andesine  Ekanite 
Cuprite  Carletonite  Calcite  Anglesite  Beryllonite  Aventurine feldspar  Moldavite 
Demantoid  Eudialyte  Carnelian  Anhydrite  Brazilianite  Axinite  Obsidian 
Diamond  Cassiterite  Catapleiite  Aragonite  Charoite  Davidite  Opal 
DjevaOte  Chalcopynte  Chalcedony  Barite  Clinohumite  Kurnakovite  
Fabulite  Leucite  Chrysoprase  Boracite  Clinozoisite  Kyanite  
Fluorite  Melinophane  Cinnabar  Celestite  Colemanite  Labradorite  
Gahnite  Phosgenite  Citrine  Cerussite  Crcolte  Microdine  
Galliant  Pyrolusite  Corundum  Chrysoberyl  Diopside  Montebrasite  
Garnet  Rutile  DiDptase  Cordierife  Epidote  Oligodase  
Gold  Scapolite  Dolomite  Danburite  Euclase  Pectolite  
Grossular  Scheelite  Friedelite  Desdoizite  Gaylussite  Rhodonite  
Hauynite  Tugtupite  Gaspeite  Diaspore  Gypsum  Sanidine  
Hessonite  Vesuvian  Hematite  Dumortierite  Hiddenite  Turquoise  
Lazurite  Wardite  Jasper  Enstatite  Hornblende  Ulexite  
Magnetite  Wulfenite  Magnesite  Eosphorite  Howlite  
Melanite  Zircon  Parisite  Hambergite  Jadeite  
Peridase  Apatite  Phenakite  Hemimorphite  Kunzite  
PoOucite  Aquamarine  Prasiolite  Hypersthene  Lazulite  
Pyrite  Benitoite  Proustite  Komerupine  Legrandite  
Pyrope  Beryl  Fyrargyrite  Lithiophilite  Malachite  
Senarmontite  Cancrinife  Ouartz  Manganotantalite  Mesolite  
Silver  Emerald  Rhodochrosite  Meerschaum  Moonstone  
Sodalite  Goshenife  Rock crystal  NathroOte  Muskovite  
Spessartite  Greenockite  Rose quartz  Peridot  Nephrite  
Sphalerite  Heliodor  Ruby  Prehnite  Neptunite  
Spinet  Jeremejewite  Sapphire  Purpurite  Orthoclase  
Topazolite  Milarite  Siderite  Sulphur  Petalite  
Tsavolite  Morganite  Smithsonite  Sinhalite  Phosphopyllite  
Uvarovite  Nepheline  Smoky quartz  Strontianite  Sapphirine  
YAG  Painite  Stichtite  Tanzanite  Serpentine  
Zirconia  Simpsonite  Tiger/s eye  TantaOte  Spodumene  
Sugilite  Tourmaline  Thulite  Staurolite  
Taaffeite  Willemite  Topaz  Talc  
Thaumasite  TriphyOne  Titanite  
Zincite  Variscite  Tremolite  
Witherite  Vivianite  
Zoisite  Vlasovite  
Zekterzite  Whewellite  
Yugawaralite 