Rock crystal is the name given to all clear colorless quartz. It is widely used as a popular ornamental stone, beads, and is also used as a gemstone. Although it is one of the lest expensive gemstone beads, cut rock crystal and rock crystal beads have been used as imitation diamonds. Rock crystal lacks the fire, color (of course) and the rarity to be ranked as a fine precious gemstone. None-the-less, rock crystal is in wide use as a gemstone due to its beauty, affordability, availability and ease of cutting. The most well known ornamental carving for rock crystal is the crystal ball of fortune telling fame.