Answer:1. Yes, there are magma of different composition in existence. silicate mineral become molten at the same temperature of 1200 degree centigrade in igneous rock formation and this does not stop the composition of magma which are of three types basalic, andesitic and rhyolitic each of them have different composition ranging between iron, magnesium and calcium.
2. Partial melting is the reason why we have different forms of rock, this is because the mantle is composed of different minerals, these minerals doesn't melt uniformly, a mineral with low melting point will turn to liquid while the one with high melting point will turn to solid crystals. As the magma melts and flow slowly before it cools into solid rock it undergoes some physical and chemical changes which causes differences in the rock formed.
3. The last question depends on ever individual's location, where i am i can easily go and see granite at a mining site that deals with construction rocks which is an example of igneous rock.
