It is smooth and velvety-black in appearance and very hard. This rock floats on water. Carbon dioxide and water dissolved in the molten rock is released with the decrease in pressure as it reaches the surface. Lava cools quite quickly in the air so the bubbles of gas get trapped. This is because overlying layers of rock insulate the magma keeping it warm, this only allows gradual cooling.
Some crystals grow to a much bigger size giving granite a speckled appearance.
8 Earthquakes, Folding and Faulting Sedimentary rock are often found tilted, folded, fractured and twisted. Large scale movements of the Earth's crust can push up whole mountain ranges. What goes up must come down' as the old saying goes, weathering will ensure that the rock cycle starts all over again.