Earth
Overall, Earth is made of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%). The 1.2% left over is made of many different kinds of other chemicals. Some rare metals (not just gold and platinum) are very valuable. Rare Earth metals are used in all types of  electronic phones and computers.