Jewelry, as a hedge, has several problems. First - you are buying at retail, and there is a huge mark-up on jewelry because it is usually an emotional purchase and retailers can get a way with it. Second - are you an expert on the different grades of gold and gems? Third - Have you been tracking anything except the price of gold? Gems, especially diamonds, have their own particular cycle. In the past, diamonds were an incredibly controlled market, with De Beers dictating the prices. I don't know the details of the current market.
In summary, don't invest in anything you have not become very knowledgeable about. Someday, I could tell you about the absolutely stupid thing I did with $14,000, but that is a tale for another day.