Question

_____________is the signature rock found only on Earth.​

Answer 1

Explanation:

Well, scientists just took one of geology's biggest controversies and shrunk it down to atomic size. By zapping single atoms of lead in a tiny zircon crystal from Australia, researchers have confirmed the crystal is the oldest rock fragment ever found on Earth — 4.375 billion years old, plus or minus 6 million years.

Answer 2

Answer:

Zircons is the oldest rock found on Earth