I've been watching the gold and silver market for years now as well. I can't say I'm shocked that both have increased significantly recently, but I'm not sure gold (or silver) is going to double within a few years.
Bitcoin shouldn't be regarded as "safe" if you're speaking about the probability of losing money by investing in it. It's never been a safe-haven asset and investors don't flock to it in times of uncertainty. The only reason why both gold and bitcoin are rocketing upward at the same time is because of all the free money that's being handed out, combined with very low interest rates. People are spending that money in the stock market, on bitcoin, and on precious metals. I don't think anything is safe right now, and all of this cheap money is scaring the hell out of me.