Well, apart from the financial security gold provides, I've never really understood why people buy so much gold jewelry. I personally just buy artificial jewelry. You can buy more of it, and it goes better with outfits rather than gold. I don't like how gold looks on me, so if I were to get anything real, it would be silver. Any gold jewelry I have are gifts from relatives, and most of them I have never used.
I wear small earrings practically everyday because I enjoy it. I actually do think certain outfits are brought to life by wearing certain jewelry pieces. Having different styles of jewelry is cheaper than having dozen of clothes. Accessories help me build different outfits with fewer pieces.
I agree though, there is no logical behind it; it's just for fun really. Just like how some people have obsession with collecting different gadgets like iPhones, iPad, Kindle, Nooks, Macbook, etc. Some people are also obsessed with designer labels.
Unfortunately, we are a rather materialistic society, so buying real gold and diamonds, an iPhone, or a BMW are symbols of status. I see people here all the time buying things they cannot afford, and then ending up in so much debt. It's sad that we put value on items rather than contents of the character of the person.