I am the official currency of a nation that was once home to one of the 'Seven Wonders of the Ancient World', and my value is closely tied to the price of a precious metal.

1. My name is derived from a term related to a heavy substance.
2. I have undergone multiple redesigns throughout my history.
3. A prominent animal known for its strength and endurance is often featured on my coins.
4. My nation's economy relies heavily on natural resource exports.