Gold is a pure element, meaning it's made up of only one type of atom. So, there are no other substances present in gold.

However, you might be thinking about alloys, which are mixtures of metals. Gold is often mixed with other metals to change its properties, like hardness or color. For example, the most common gold alloy is 14k gold, which is a mixture of:

* Gold: Usually around 58.3%

* Other metals: Typically copper, silver, and sometimes zinc or nickel.

Let me know if you'd like to learn more about gold alloys!