It takes a lot of effort, and a certain amount of luck, to see some of the rarest things on Earth. Some things you only experience once in a lifetime, and then there are things that almost no one has seen. From gemstones to baseball cards to wine, these objects run the gamut. But how is rarity determined? Usually it comes down to availability and price, but some coveted objects and natural phenomena are priceless. Here are some of the rarest things ever found on Earth. Don’t forget to SHARE this post with every collector you know.

Editor's Note: This was first published on May 31, 2016.