A Gemstone (also called a fine Gem, Precious Stone, Semi-precious Stone) is a piece of mineral crystal which in cut and polished form is used to make jewellery or other adornments. However, certain rocks (such as lapis lazuli and opal) and occasionally organic materials that are not minerals (such as Amber, Jade, and Pearl) are also used for jewellery and are therefore often considered to be Gemstones as well.
Most Gemstones are hard but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to Gemstones any of various minerals highly prized for beauty, durability, and rarity. A few noncrystalline materials of organic origin (i.e. Pearl, Red Coral and Amber) also are classified as Gemstones.