Question

Which statement is an opinion?

It is roughly the size of a tabletop . . .
[T]his rather small piece of rock was more valuable than any of the larger objects in the room.
Next to the statues and the head
three feet nine inches long, two feet four and a half inches wide, and eleven inches thick.

Answer 1

"This rather small piece of rock was more valuable than any of the larger objects in the room."

Because the rest of the statements are stating facts about the object.