Quartz, SiO2, and Calcite, CaCO3. Dylife mine, Central Wales Orefield. Clear druzy quartz crystals with a uniform size of about 1mm. on the front and rear of a piece of host rock. There are several small deposits of calcite on top of the druzy quartz. The quartz and calcite were deposited from hydrothermal circulating fluids at depth with the quartz being deposited first. Finer detail of the calcite is to be seen in Quartz( druzy) and Calcite 2.