1. Copper colors many minerals blue, green, or turquoise. Which of these minerals contains copper? It is a very common copper mineral in Arizona. This sample is from the Ray Mine in Pinal County, Arizona.

Chrysocolla has the complicated chemical formula of Cu_2−xAl_x(H_2−xSi₂O₅)(OH)₄·nH₂O (x<1).

Chrysocolla can be blue, cyan or blue-green, green, blackish blue to black, or brown, and sometimes yellow.

The mineral hardness scale runs from 0 to 10, and chrysocolla has a hardness between 2.5 and 7. That’s a wide range for a mineral, and the hardness depends on just how it forms.

If you rub a piece of chrysocolla on a piece of white clay, you’d see that it leaves a white to a blue-green streak. DON’T do this without permission!

It has been used in jewelry since ancient times. Because it can be blue like turquoise, but is more common, it has often been used as a turquoise substitute.

Chrysocolla forms underground from copper changing as it becomes exposed to other minerals. Sometimes it is mined as copper ore, but it’s not a very good ore.

Arizona is one of the major producers of chrysocolla.