How old is serpentine rock?

Serpentine rock is typically formed from the alteration of ultramafic rocks, such as peridotite, through a process called serpentinization. This process can occur over a range of geological time scales, often taking millions of years. As a result, serpentine rocks can be found in formations that are hundreds of millions to over a billion years old, depending on the specific geological context in which they were formed.