Beautiful deep blue shattuckite and bright teal Chrysocolla with Quartz Milpillas Mine, Cuitaca, Sonora, Mexico 992 Level, Milpillas Mine. this is a high quality piece these are very expensive Shattuckite is a relatively rare copper silicate mineral. It was first discovered in 1915 in the copper mines of Bisbee, Arizona, specifically the Shattuck Mine (hence the name). It is a secondary mineral that forms from the alteration of other secondary minerals. Shattuckite from the Milpillas mine is considered expensive because it is a relatively rare mineral, particularly when found in high-quality, vibrant blue specimens, and the Milpillas mine is currently one of the most prolific sources of this specific type of Shattuckite, making it highly sought after by collectors due to its exceptional color and crystal formations.