RuneScape Classic Wiki
The Old School RuneScape Wiki also has an article on Iron ore.
The main RuneScape Wiki has an article on: Iron ore

Iron ore is an item which can be mined by players with level 15 mining from an iron rock. Iron ore is used to create iron bars, as well as steel bars using two lumps of coal and one iron ore on a furnace. Unlike the other types of ore, iron ore has a 50% (or 100% if using Superheat item) chance of creating an iron bar when smelting.

For a list of iron rock locations, see iron rock locations.

Iron ore can be exchanged for iron ore certificates by talking to Giles at the Draynor Village market.

Two iron ore are required for Doric's Quest.

Dropped by

They are dropped by:

Monster Combat level Quantity Rarity
Dwarf 18 1 3Uncommon
Dark Warrior 21 1 2Common
Guard 28 1 3Uncommon
Mountain Dwarf 28 1 3Uncommon
Skeleton 25 1 3Uncommon
Thug 18 1 2Common
White Knight 56 1 3Uncommon

Sold in

Store Location Stock
Drogo's Mining Emporium Dwarven Mine 0