Most mineral gemstones are crystalline with their atoms arranged in regular and symmetrical patterns. A few minerals are present in amorphous shapes, which are not crystalline forms. These most common amorphous minerals are Obsidian, Tektites, Amber, Opal & Ivory, which have an irregular shape. Rest majority of the gemstones are present in their individual crystalline forms. There are seven types of crystal structures. These following seven crystal types are given with some common gemstones, which are present in it.

• Cubic: Diamond, Garnet, Spinel, Fluorite, Etc.
• Tetragonal: Zircon, Scapolite, Etc.
• Trigonal: Ruby, Sapphire, Amethyst, Citrine, Tourmaline, Etc.
• Hexagonal: Emerald, Aquamarine, Apatite, Etc.
• Orthorhombic: Topaz, Peridot, Chrysoberyl, Iolite, Etc.
• Monoclinic: Diopside, Jade, Malachite, Etc.
• Triclinic: Turquoise, Kyanite, Labradorite, Etc.