Experiment - Does the rock contain copper?

Our Rock Specimen

Our Rock Specimen

When we were out walking the dog one day after school, we found a rock that had a funny green tinge to it. We wondered why it might be green. Our teacher told us it might be green because it contains copper. We conducted an experiment to find out.

At school, with the help of our teacher, we put the rock in a beaker and covered it with dilute acid. The label on the bottle said "Sulphuric acid 1M H2SO4". After a few minutes, the liquid turned blue!

Malachite

Malachite

Next we put some steel wool into the beaker. The liquid turned from a dark to a pale blue, and the steel wool went a copper-red colour.

We think that the acid turned blue because something in the rock was reacting with it. We think the rock must have contained copper, and that the copper reacted with the acid to make copper sulphate solution (chemical formula = CuSO4). (Copper sulphate is blue.)

Then when we added the steel wool, the copper came back out of the solution and stuck to the outside of the steel wool, making it turn a copper colour. We think that there definitely was copper in the rock that we found!

Joshua Seger and Kate Nicks, year 7.

NEXT: Read about how Copper is used, or do the next quiz question.

Minerals Downunder Copper Contents