The Secret Between USD and Gold

The reason why this will happen is because Gold is priced in U.S. Dollars. Thus, if the value of the U.S. Dollar goes down, more of those Dollars are needed to buy the same amount of Gold, so the price of Gold instantly goes up; conversely, if the U.S. Dollar goes up, the price of Gold goes down. It's a direct, mathematical relationship. To understand the relationship more precisely, the Dollar has an "inverse" affect on Gold. While it's true that a 1% drop in the Dollar would basically mean a 1% rise in Gold.

Gold
There is sometimes that Gold will be outperform than the USD it is because Gold has its own supply and demand fundamentals as well. These are factors affecting the Price of Gold that have less of an affect on the U.S. dollar such as changes in demand for gold for jewelry or for industrial or dental applications, increases or decreases in mining and others.

US Dollar
The USD used to be considered the safe haven because of US being the largest and the most reputable country but not anymore and many people are shifting they money towards Gold because it can resists against worldwide economic shocks or tensions.