With crystals large enough to be seen, granite is an attractive mixture of very light quartz and feldspar crystals, along with some darker crystals which are usually mica and hornblende. Granite is very solid and hard because it tends to have no cracks or seams. Unlike most other rocks, granite can support great weight because it does not easily crack. Rhyolite is chemically similar to granite, but has much smaller crystals. More on granite.
Granite is original and underived.
A key factor is that granite, when melted and rehardened, changes into rhyolite. For this reason, it is impossible for scientists to artificially produce granite. Another special quality of granite is that it never contains any fossils. Granite is the bedrock undergirding all continents. But recently it has been discovered that the granite keeps going down, far below the Conrad discontinuity.