Gold is great for locking up wealth. Its shot up over recent years primarily because its used as a hedge for the rest of the stock market. Investors park their money up in gold when the rest of the market is tanking or currency is devaluing.
When the rest of the market improves you see the gold getting liquidated.
I was buying gold when it was about $700 an ounce . There was quite a lot of talk as to why Gold was so pricey ( lack of confidence in the rest of the market basically and people looking for better long term investment than property).
Quite a few people and companies reckon it costs about $600 an ounce to get the gold out of the ground ( which is actually quite pricey) however a lot of gold ( most of it possibly) is obtained as a consequence of other metal mining ( copper for example).
Pretty much all the gold in the world is still in existence , silver and platinum by comparison are destroyed in industrial processes and are not used for the same type of safe have "gold standard" that gold offers.
ETFs are often differentiated from physical gold holdings as ETFs do not necessarily reflect true gols availability as they are not actually backed with real physical gold but rather are a companies promise to honour such ( like fiat money). However you can short the market as well with ETFs. If you tried to exchange all the etfs in circulation for physical gold you would probably find that there was a shortfall.
So people who buy gold are mixed, hedge funds looking for a safe haven parking space for money whilst the rest of the market improves , then you have long term investors , then you have China using it to lock up wealth away from the influence of western markets and industry, and last of all you have the crazy people who believe the end of the world is coming and the only way to buy a loaf of bread is with Krug , brittania , eagle or other solid gold coin.
I use goldmoney for buying gold as its cheaper than walking into a bullion dealer and I can buy and sell it immediately , its also backed by physical gold , you own the actual gold itself not just a promise to pay.
I made 12k profit from a 60k investment in gold not that long ago. If I hadn't tried to be clever it would have been 17k.
My suspicion is that gold is going up for a bit longer.