Dust,Nugt-inverse, tracks miners, so.. nugt is not exacting science for tracking spot but I like to use spot as an overall barometer, as the relation of gold price and cost to extract, plays a role for miners.
Vix comparison, not so sure if there is a distinct pattern correlation, correct me of I am wrong). Though wouldn't discount volatility plays a role in some form or fashion linking back to markets and flight to safety instruments. http://etfdb.com/tool/etf-comparison/DUST-VXX/