Over the years, experts have identified an assortment of the world's most ancient items, ranging from the earliest prosthetic (two artificial toes dating back to Ancient Egypt) to the world's first known song (a Sumerian hymn written 3400 years ago). But what's the oldest thing ever found? It depends on whether you're talking about geological objects or man-made objects—and in this particular instance, the term "man" (or even "human") isn't quite accurate.

In 2014, scientists confirmed that a small zircon crystal found on a sheep ranch in Western Australia was actually a 4.4-billion-year-old piece of the Earth's crust. This made it the oldest rock fragment ever found on Earth. In comparison, our earliest fossils are only 3.5 billion years old.

Meanwhile, in 2011 a team of archaeologists unearthed stone tools in Kenya that are 3.3 million years old. Since the human Homo genus only emerged about 2.8 million years ago, it's thought that they were fashioned by an earlier human relative. The discovery challenges the idea that the main characteristics that make us human, such as "making stone tools, eating more meat, maybe using language—all evolved at once in a punctuated way, near the origins of the genus Homo,” Jason Lewis, a paleoanthropologist at Rutgers University who was involved with the find, told Smithsonian.

In short, we're constantly finding new objects that refine the timeline of Earth (and humanity). For now, the Australian crystal and the stone tools are some of the oldest things ever found. But who knows? Maybe in a few years, they'll simply be old news.

[h/t CNN, Smithsonian]