When most people think of gold, they automatically think of yellow gold. It's the reason why blonde hair is sometimes referred to as golden one beautiful yellow flower is called a goldenrod. However, whenever you go shopping for jewelry or collect a variety of coins, you'll quickly notice that not all gold is bright yellow.

In fact, gold can come in a variety of colors and hues. This is because the gold pieces that most people own are not pure gold, but instead a mixture of pure gold with another metal. The mixture of metals is referred to as an alloy, and depending on what the components, the proprieties of the gold piece vary, including the color.

Yellow gold is made when pure gold is mixed with other metals like copper and zinc. Yellow golds of varying karats may have different alloys and will certainly have varied amounts of each metal. For instance, 22 karat yellow gold may contain 92 percent pure gold, 4.2 percent silver and 4.2 percent copper. Yellow gold of only 14 karats, though, may have 58 percent gold and then higher percentage of copper than silver.

Rose gold is likely the second most popular gold color. A gold piece gets its rosy glow when the alloy contains copper. The more copper that is added, the more reddish the gold will appear.

"Alloy metal suppliers will vary the copper, but whether you call it red, pink or rose gold, it's all the same process. Rose gold is more rare, whether that's because it's made to order or there's just less of it being made," the director of jewelry promotion for the World Gold Council, Duvall O'Steen, explained to the Los Angeles Times.

White gold is another common gold color, and is typically formed using copper and zinc. However, white gold jewelry is often coated with a metal called rhodium to make it look more white.