While gold is valued based on the market-determined price of refined raw gold, the form of your gold may increase in value beyond that price. Gold in the form of large nuggets or rare bars are more valuable than standard bars or small nuggets of gold.
Gold Nuggets
Gold nuggets are naturally occurring pieces of gold whose rarity increases drastically with size. Because of this rarity, gold nuggets always cost more than their gold content.
Gold Bars
Gold bars are any cast or minted gold made by a recognized manufacturer. Different types of minted bars are available that vary in purity, but they are all generally valued at a premium lower than their pure gold content.
Value Comparison
While gold nuggets are generally more valuable than gold bars, particularly if they are large and rare nuggets, if your gold bar is a rare gold coin it could be worth more than a gold nugget. If, however, you own a standard gold bar, a gold nugget is more valuable.