Shattukite (rare), sometimes also called “Quattro Quantum” split bracelet from South Africa

The mineral shattuckite is a copper silicate with the chemical formula Cu5Si4O12(OH)2. The mineral belongs to the inosilicates. The transparent to translucent (dark) blue or green shattuckite has a vitreous luster, a blue streak color, and the cleavage is perfect along the crystal planes [100] and [010]. The average density is 3.8, the crystal system is orthorhombic, and the mineral is not radioactive. Shattuckite is a secondary mineral formed near malachite deposits. The type locality is the Shattuck Mine, near Bisbee, Cochise County, Arizona, United States.