Nature Done Wright

On Monday I wrote that this rock is from southern Bergen County.  What is it, and where is it from?

The answer is copper, from the historic Schuyler Mine in North Arlington.

Fran Duggan said it was copper from the Schuyler Mine in North Arlington. Nils Abate thought it was Chrysocolla from the Schuyler Copper Mine in North Arlington, and Marianne Hermann agreed, but wondered: "But should it be called Pseudomalachite or Psilomelane?"   

Her question is beyond my pay grade, which isn't saying much, since I do this blog for free.  As a fledgling geology guy, all three answers work for me. A rock expert adds:

"Both chrysocolla and pseudomalachite occur at the Schuyler mine. They are impossible to differentiate based on the general photo you posted. But the botryoidal habit visible under high magnification is typical of pseudomalachite. Additionally chrysocolla is a silicate and should not react to HCL acid. Pseudomalachite is a phosphate and should fizz upon application of a drop of HCL.

"Most specimens have both species present."

Ginny Chucka said it was the chunk of copper she saw in the trunk of my car at last weekend's Franklin Clove walk. She is correct as well, and had the funniest answer.

Thanks to all!