Quartz crystals Quartz has transparent or transluscent hexagonal crystals, either with a sharp point, or a flat edge. All edges tend to be sharp and the surfaces smooth. They are often packed together, grwoing in parallel. Single crystals can be broken off and sold, like this one.
Quartz crystals come in many different sizes.
On the right is another crystal formation. A crystal has formed, then stopped, then carried on growing. From the specimens on this page, you can see the normal shape of a quartz crystal. This specimen on the right is a Herkimer Diamond. They are found at Little Falls, New York.