The latest dinosaur being mounted at the Natural History Museum in Los Angeles is not only a member of a new species—it’s also the only one found on the planet whose bones are green, according to museum officials.

Named “Gnatalie” (pronounced Natalie) for the gnats that swarmed during the excavation, the long-necked, long-tailed herbivorous dinosaur’s fossils got its unique coloration, a dark mottled olive green, from the mineral celadonite during the fossilization process.

While fossils are typically brown from silica or black from iron minerals, green is rare because celadonite forms in volcanic or hydrothermal conditions that typically destroy buried bones. The celadonite entered the fossils when volcanic activity around 50 million to 80 million years ago made it hot enough to replace a previous mineral.

The dinosaur lived 150 million years ago in the late Jurassic Era, making it older than Tyrannosaurus rex—which lived 66 million to 68 million years ago.