Shattuckite is a copper silicate mineral with the chemical formula Cu₅(SiO₃)₄(OH)₂. It is known for its vibrant blue to blue-green color and often occurs alongside other copper minerals such as malachite, chrysocolla, and azurite. Shattuckite forms in the oxidation zones of copper ore deposits and has a Mohs hardness of 3.5 to 4, making it relatively soft and best suited for carvings or cabochon jewelry rather than faceted gemstones. Major sources include Namibia, the Democratic Republic of the Congo, and the United States (Arizona). It is prized for its rich color and intricate patterns when polished.