Gemstone

A gemstone, gem or also called precious or semi-precious stone is a highly attractive and valuable piece of mineral, which -- when cut and polished -- is used in jewelry or other adornments. However certain rocks, (such as lapis-lazuli) and organic materials (such as amber or jet) are strictly speaking not minerals, but are still applied in jewelry and adornments, and are therefore often considered a gemstone as well. Some minerals that are too soft to be generally applied in jewelry may still be considered a gemstone because of their remarkable color, luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone.