The mineral to the left is Barite. When the barium in this mineral is replaced by Strontium the Barite changes to Celestine.

Move your mouse over the Barite photo to the left to see Celestine.

If subjected to circulating solutions with high oxygen contents, Chalcopyrite, shown to the left, is transformed into Malachite.

Move your mouse over the Chalcopyrite photo to the left to see Malachite.