Although we do have one old sample that parallels it-from a mine in your territory.

And there's no way of predicting when new technology will suddenly make old samples valuable.

Still, why the interest in the old samples?

"I have some old samples lying around," he said.

Keeping such material will allow scientists to apply what they learn in coming years to old samples.

Many older samples, however, have been found to be potassium alum.

The test is very sensitive and can detect tiny traces even in old samples.

This find is one of the oldest human genetic samples recovered in the Americas.

The oldest samples, found in Nebraska, date to about 15 million years ago.

Uranium-lead dating is applied to samples older than about 1 million years.