I had previously encountered that website, which certainly is, to my
knowledge, the premier Copper Culture artifact collection online.
Those who haven't clicked on the link should do so, and gaze in awe at
the material assembled there.

Here's another link re Copper Culture - this one less reality-based
and a little more toward the "fringe" (but still interesting)...

http://www.geocities.com/stoahist/Acheron.html