Quartz (SiO2, or Silicon dioxide) is the most common mineral found on the surface of the earth. It can be found in many formations and colorations. It is a hexagonal crystal, due to its molecules being hexagonal in shape themselves. The long faces of the prism section of a quartz crystal will always form a 60 degree angle due to these molecules. The higher the quality of quartz, the more perfect the peaks and overall shape. Synthetic and "perfect" quartz can be formed in an autoclave in the same basic process as synthetic emerald.