I guess most of it depends on the demand and supply of things. Gold and bitcoin are completely two different things, and gold going down has a very little or nothing to do with bitcoin going up. You might consider reading this for some more info on gold prices : http://www.economist.com/blogs/economist-explains/2015/07/economist-explains-17 .
Though the trend for btc going up is because of other reasons, that include high demand due to FBI auction(people might expect btc to crash afterwards and so they are buying right now) and halvening that will create a low volume of bitcoin in the market.