Quartzite, with a Mohs hardness of seven along with greater toughness, is superior to both in many uses. In architecture, marble and granite have been the favorite materials for thousands of years. This is a characteristic that separates true quartzite from sandstone. It is so tough that it breaks through the quartz grains rather than breaking along the boundaries between them. The interlocking crystalline structure of Quartzite makes it a hard, tough, durable rock. It often occurs as silicified sandstone, as in sarsen stones. Quartzite stone is an extremely compact, hard, granular rock consisting essentially of quartz.
