1. Quartzite is harder than marble: quartzite has an average hardness of 7 on the Mohs scale, while marble only has a hardness of around 3. This means that quartzite is much more resistant to scratches and wear.

2. Formation by metamorphosis: Quartzite is formed when sandstone is transformed into an extremely hard rock by high pressure and high temperatures deep in the earth's crust.

3. Difference to sandstone: Although quartzite and sandstone both consist of quartz, quartzite is much denser and less porous than sandstone. This makes quartzite more resistant to stains and moisture.

4. Variety of colors: pure quartzite is white, but due to impurities such as iron oxide, clay and other minerals, it can occur in different colors such as pink, red, yellow and green.

5. Use in architecture: Due to its hardness and aesthetics, quartzite is often used for countertops, flooring and wall cladding. It offers the beauty of marble with the durability of granite.

6. Quartzite vs. quartz: Quartzite is a natural rock, while quartz is a man-made material made from quartz crystals and resin. Both have different properties and applications.

7. Geological deposits: Quartzite occurs worldwide, especially in Brazil and India. In Germany, quartzite can be found in the Taunus and Harz mountains, among others.

8. Confusion with other rocks: Due to its similarity, quartzite is sometimes mistakenly sold as marble or granite. A simple test with a piece of glass can help to identify quartzite, as it is harder than glass and scratches it easily.