It seems that the cable is made of copper and only the terminal is made of silver or goldThere are several ones on this forum. Here is one I could find with a quick search:
Audioquest GO-4 Speaker Cable Review
This is a review and detailed measurements of the AudioQuest GO-4 speaker cable. It is on kind loan from a member and costs about US $599. The attached dongle is a 72 volt battery supply that feeds an unterminated wire the length of the cable. Different terminations can be ordered. Here are...www.audiosciencereview.com