Wire is wire. Resistance is all you need to worry about, so save yourself a lot of money and buy some low cost speaker wire of the appropriate gauge.
Not a single person in this thread could discern a difference in a proper test.
Pure Silver Wire
If silver is so good to use why do we not see solid silver speaker cables? Price is not that high- 10ga diameter pure silver 6ft is just under $300. That makes a pair of speaker cables about $1,100 for material. I see the price of some of these cables on the market and $1,100 is a fraction of their asking price.