Azurite is a mineral formed by oxidation in copper bearing deposits, a secondary copper mineral with chemical formula Cu3(CO3)2(OH)2. It is monoclinic and is often found as tabular or prismatic crystals in a lustrous deep blue color, but may also form non-crystalline crusts. Like in this sample it often occurs together with malachite, chemical formula Cu2CO3(OH)2., the other colorful secondary copper mineral, known for its attractive green color. Other than azurite, malachite is nearly always an amorphous precipitate, crystals are very rare. The substrate on which the minerals have here precipitated is a red volcanic rock