Crown gold is a special type of gold that was used a long time ago to make special coins called "crowns". These crowns were very valuable and were used by kings and queens.
Crown gold is very shiny and pretty because it is made up of mostly gold, which is a very valuable metal. But it has a special mix of other metals in it, like copper, to make it harder and strong enough to make into coins.
Nowadays, we don't really use crown gold anymore because we don't make those special coins. But we still use regular gold for jewelry and other things because it is still very valuable and looks really nice.