A gemstone is the naturally occurring crystalline form of a mineral, which is desirable for its beauty, valuable in its rarity and durable enough to be enjoyed for generations.It is a piece of attractive mineral, which when cut and polished is used to make jewelry or other adornments.Most gemstones are hard, but some soft minerals are used in jewelry because of their lustre or other physical properties that have aesthetic value.Rarity is another characteristic that lends value to a gemstone