Figure 2.04. Wollastonite skarn. Grossularite garnet (dark red) and diopside (green) and wollastonite white form layers in a skarn mined in Willsboro, NY, USA. The skarn formed at a contact between marble and an anorthosite intrusion. Use your mousewheel to zoom and pan to see details. Click on the "Show Hres" button to see a higher resolution view. John Brady photo.