Mixite is a rare copper bismuth arsenate mineral with formula: BiCu₆(AsO₄)₃(OH)₆·3(H₂O). It crystallizes in the hexagonal crystal system typically occurring as radiating acicular prisms and massive encrustations. The color varies from white to various shades of green and blue. It has a Mohs hardness of 3.5 to 4 and a specific gravity of 3.8. It has an uneven fracture and a brilliant to adamantine luster.