Re: zakat for gold
You dont calculate for the gold seperately, but combine it with the rest of your wealth. There is a minimum limit, called the nisaab, if your wealth is over the limit of nisaab for over a lunar year, then you pay 2.5% of its total worth in zakat. I dont know what the nisaab is exactly now, something about $1,000 perhaps. So if you buy even a small amount of gold you will probably be over the limit and have to pay. But you dont calculate your gold wealth seperately from your cash wealth. Like if you have $10,000 in the bank and only $500 worth of gold, you dont say that your gold is under nisaab so you dont have to pay on that, you have to combine all the wealth first and then take 2.5% of that
If you really dont want to pay zakat, then you can convert all your wealth into diamonds 
But I dont see paying zakat as something we should try to get out of or avoid --its a great thing and a huge blessing to actually BE a person who is supposed to pay zakat --because only imagine if you were on the other side, as a person who is in need of zakat!!