The price of Gold generally goes up when the markets go down, as investors think it will hold its value if stocks start to fall.
Since 1979, the S&P 500 grew 13 times faster than the price of Gold. However, during the last market crash, Gold almost doubled its price (from its lowest to highest points), while the S&P 500 lost half of its value (from the highest to its lowest point).
If you are worried about a stock crash, gold might be a good place to invest. If you think the stock market is strong, stick to stocks, mutual funds, and ETFs!