Researchers recently studied 2,550 of the rarest minerals on the planet.

Scientists have cataloged 2,550 of the rarest minerals on Earth; some of which are believed to have a worldwide supply smaller than a sugar cube. 
Of course that makes these minerals much more precious than almost any diamond, but that doesn't mean they're the sort of rock you'd want to stick in an engagement ring. 
According to a summary of the findings, "Several are prone to melt, evaporate or dehydrate. And a few, vampire-like, gradually decompose on exposure to sunlight." 
Researchers at the Carnegie Institution for Science and The Rockefeller University say the rare minerals' greatest assets are the stories they tell us about the conditions in the sub-surface areas they dwell, in addition to clues ab