There’s something about gold that endures. You can freeze it, light it on fire, hammer it flat, spit on it, and it still remains itself. That’s a big reason why we love it, and why we collect it. We live in a world that moves fast and things change even faster. But gold remains.

That might be a big reason why you want to collect rare gold coins. But trust us when we tell you that it’s not always quite so simple to just buy a coin. Read on for 5 more tips to bear in mind when buying gold coins.

1. The same coins aren’t always made during the same years. For example, the San Francisco mint produced 6 unique denominations of gold coins, but there were only 4 years in which all 6 were made at the same time. Not always, but sometimes having a complete year set can drive up the value.

2. Color is an important indicator for value. Certain coins made during certain years will have a particular shade of gold to them. Your job is to make sure you know the right shade. You can learn about shading online, at the ANA Museum in Colorado Springs, and by viewing catalogs with older collections, like Norweb, Bass, and Eliasberg.

3. There’s a difference between regular wear as opposed to strike. Look at photo archives of coins. If you start noticing the same imperfections found on roughly the same spots on the coins, that’s strike.

4. There can sometimes be a mania with collecting, where people are willing to spend money, a lot of money, to complete a series or collection. When it comes to spending your hard-earned money, be willing to walk away, and trust that you’ll find the coin you want somewhere else for a more reasonable price.

5. For a while, larger sized coins seemed to have more value than smaller coins. Does that mean that size really does matter? If they’re part of a series, perhaps.