10 Rarest Things Ever Discovered

Some discoveries are so weird and so specific that nature basically went, “You better pay attention because I’m only going to show this thing one time,” and meant it. These one-of-a-kind finds confuse scientists, break theories, and make the rest of us feel like we’re living in a never-ending side quest.

From a penguin that looks like it escaped a lemonade commercial to a literal glass brain, here are ten things that, as far as we know, have only ever shown up once in the history of the universe.

A Yellow Penguin

In 2019, photographer Yves Adams was snapping king penguins on South Georgia Island when one bird showed up looking like it had wandered out of a highlighter factory. Instead of black and white, this penguin was mostly white and glowing golden-yellow. Experts think it has leucism, a pigment disorder that wipes out melanin in some feathers and turns normally dark areas yellow. Cases like this are believed to be rarer than “one in tens of thousands,” and this is the only documented yellow king penguin in the world. One could say it’s the shiny version of a regular penguin.

Gwada-Negative

In 2025, a patient in Guadeloupe baffled lab techs when her blood refused to match any known donor sample, including those from her own siblings. After running genetic tests, scientists figured out why. A mutation had removed a specific sugar molecule from her red blood cells, creating an entirely new blood group. It didn’t fit into any of the 48 recognized systems, so it got its own name: Gwada-Negative. Right now, she’s the only known person in the world with this blood type. Since there are no compatible donors, a transfusion would be incredibly risky.

Kyawthuite

The rarest mineral on Earth is a tiny orange crystal someone almost ignored at a gem market in Myanmar. In 2010, a geologist bought what he thought was ordinary scheelite. Once it was cut and analyzed, nothing made any sense. The Gemological Institute of America eventually figured out it was natural bismuth antimonate, previously only known as a man-made material. Officially named “kyawthuite” in 2015, it weighs about one-third of a gram and is still the only known specimen. It likely formed under incredibly specific volcanic conditions we can’t yet reproduce, which is science’s polite way of saying, “No idea how the planet did this.”