No, they do not contain fake gold but they are not pure gold. The purity is measured by karats. 14 karat gold which is used for jewelry for example is 14 parts gold and 10 parts other metal such as...
24 karat gold - 100% Au - pure gold, very soft and very easily bent, too soft for jewelry. Therefore the gold is alloyed with silver, copper, nickel or zinc: 22 karat gold - 91.7% Au - still too soft...