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.
Chicago imposed a height limit of 40 meters in 1893, but New York raced ahead with large and tall blocks. Many of these, such as the Singer, Woolworth, MetLife and Chrysler buildings, tapered off with campanile towers, battling to be tallest in the world. The first skyscraper to break the half-kilometer mark, the world's tallest building between March 2004 and March 2010 is also one of the greenest -- certified LEED platinum in 2011.