Sandstone is a rock that is made of sand sized fragments of rock that are cemented together. The fragments don’t have to be made of quartz sand. They can be just about any mineral or even rock fragments containing more than one mineral. On the other hand, quartzite is a rock that is made up almost entirely of macroscopic quarts crystals. Most quartzite is metamorphosed quartz sandstone. However, some can be purely sedimentary. In sedimentary quartzite, the sand grains are held together by quartz cement. One of the easiest ways to tell the difference between a nearly pure quartz sandstone and quartzite is to examine a broken surface. With sand stone, the cement is softer than the quartz grains. So, it breaks around the grains. On the other hand, the hardness of a quartzite is fairly uniform. So, it will break through the quartz grains.