At one time humans thought the earth was flat and you could be put to death if you said other wise, the lesson is that we should never say this is that and thats the end of the story because usually it isn't the end of the story, heck maybe most of the things we 'think" we know now may turn out to be wrong, who knows.
Most of those look like rocks, but maybe in 1000 years we might have a more advanced way to analyze them if they happen to be still around and find out they were actually artifacts of some type or just rocks.
Its better to say , in my opinion these look like artifacts, others say in their opinion they look like rocks, either way is fine as long as we don't start burning people at the stake (again) because we don't like their opinion.
Then again what do I know.