An X-ray study of the domeykite group*

Domeykite, algodonite and whitneyite are usually considered as definite minerals, and have been assigned the formulas Cu₃As, Cu₆As and Cu₉As, respectively. However, various investigators have questioned the existence of these compounds, and have reported that microscopic examination reveals that these minerals are mixtures, rather than homogeneous compounds. In this present investigation, X-ray methods have been used to supplement the microscopic data, and rather conclusive information regarding these minerals has been obtained.