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 Dubai Towerâs 160-stories reach 828 meters high (2,716 feet) â a height kept secret until the opening Monday night. The towering statistics, by contrast, have spilled across the media. Itâs so tall that itâs visible from 60 miles away, reports say, and the temperature drops 6 degrees from base to peak.