I am the official currency of a nation that is home to the world's largest continuous sand desert, the Rub' al Khali, and also has a significant portion of its territory covered by the Empty Quarter. This country is known for its historical significance as the birthplace of Islam and houses the two holiest sites in the religion.

1. My value is pegged to the US dollar.
2. My name is shared with a former unit of currency used in many regions.
3. The central bank issuing me is the Saudi Central Bank.
4. My current form was introduced in 1960.