Metamorphic rocks have been modified by heat, pressure and chemical processes, usually while buried deep below Earth's surface. Exposure to these extreme conditions has altered the mineralogy, texture and chemical composition of the rocks. There are two basic types of metamorphic rocks.Foliated metamorphic rocks such as gneiss, phyllite, schist, and slate have a layered or banded appearance that is produced by exposure to heat and directed pressure.uartzite is a non-foliated metamorphic rock that is produced by the metamorphism of sandstone. It is composed primarily of quartz. The specimen above is about two inches (five centimeters) across.
Sydney Tower. Sydney Tower is Sydney's tallest structure and the second tallest observation tower in the Southern Hemisphere. Auckland's Sky Tower is taller but Sydney Tower's main observation deck is almost 50 m (164 ft) higher than the observation deck on Auckland's Sky Tower.
The Sydney Tower has been an integral feature of the Sydney skyline for over 30 years. Measuring 309 metres at its highest point, it is one of the tallest structures in the southern hemisphere and by far the tallest building in Sydney. More about Sydney Tower.