The blue on this piece and the green on a malachite are the same element doing different things.
Copper is unusual among metals in that its compounds are almost always coloured, and the shade depends entirely on what it has bonded with and how much water is caught up in the structure. Bond it to carbonate one way and you get the deep blue of azurite. Bond it to carbonate another way and you get malachite green. Add silica and water and it shifts to the softer blue-green of chrysocolla. Bring zinc into it and you get the pale, chalky blue of aurichalcite.
One element, one mine, and a range of colours that has nothing to do with different metals being present. Just different arrangements of the same one.
Very soft, and copper minerals are toxic if swallowed. Dust with a dry brush rather than washing, keep it away from children and pets, and wash your hands after handling.
Mineral: Calcite (calcium carbonate, CaCO₃) with blue copper minerals
Crystal system: Trigonal (calcite)
Origin: Río Tinto Mine, Labor de Terrazas, Chihuahua Municipality, Chihuahua, Mexico
Hardness: Calcite is 3 on the Mohs scale and the blue coating is softer
Treatment: None
Dimensions: 11.15 x 5 x 13.8 cm
Weight: 0.355 kg
You will receive the exact piece photographed.