Lapis lazuli, or lapis for short, is a deep blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color. At the end of the Middle Ages, lapis lazuli began to be exported to Europe, where it was ground into powder and made into ultramarine, the finest and most expensive of all blue pigments. It was used by some of the most important artists of the Renaissance. Lapis Lazuli is rated between 5 and 5.5 on the Mohs hardness scale. Lapis Lazuli is associated with truth and wisdom and is thought to promote honesty, friendship, socialization, and dignity.