On an Occurrence of Rare Copper Minerals from Utah

Extract

In the American Eagle Mine, Utah Territory, occur in intimate association with olivenite and other copper compounds, two copper minerals of an interesting and rare composition.

Covering the surface of often large pieces of more or less friable mixed arseniates, sometimes forming a complete green coating, are numbers of beautiful emerald-green globules. In consequence of the firm adherence of the base of the globules to the underlying gangue matter, it was difficult to obtain material pure enough for analysis, and therefore the results given below lay no claim to great accuracy.