Polarised light micrograph of Val Gardena sandstone from the Moeltner Joch quarry near Meran, South Tyrol, Italy. Sandstones from the Val Gardena formation are medium to fine-grained. They are a weathering product of Etchtal quartz porphyry that was deposited by meandering river systems about 260 million years ago. The rock contains partially petrified plants. The main components are quartz (white and blue) and feldspar (dark fine structures), with some mica (striped). Magnification: x60 when printed at 15 centimetres wide.