Do cystine stones reoccure as you age?

This term is used to denote a culture that does NOT use metal tools, presumably because they do not know how to make metal.

This period of time was when humans primarily relied on stone and pebble tools.

because the people of that time used stone tools, but during the new stone age they used metal tools, so im confused 2 :)

There's actually three parts to the Stone Age. There's the Old Stone Age, the Middle Stone Age, and the New Stone Age. To learn more about them you can Google them, there actually pretty interesting!

The Stone Age was a broad prehistoric period where humans widely used stones and stone making for many different types of tools.