Iron ore is the next ore after Bronzium. It's a bit faster, and it's grayish-tan. It can be found about 90 blocks underground (If you're at around depth=450). It's Bars can be used to make things such as Candles and Chains. One iron ore sells for 1 silver. However, since these are a starter item, and they are only Blue tier, they're not a very good ore to keep.