That's kind of a loose question, but a 2 drop ar process with all your t's crossed and i's dotted will get you 995. That's good enough for good delivery grade gold bars on the market. Anything above that unless you need it for purer purposes is not worth the effort as far as monetary purposes. You want 999 do a 2-3 step ar drop and uses different precipitates for each ar step. Your want 9999 go with a gold cell.
There is some leeway regarding what constitutes fine gold. As 100% pure gold is virtually impossible to achieve, the purest type of gold currently commercially available is 999.99. This is sometimes referred to as five nines fine. The Royal Canadian Mint regularly produces commemorative coins from this fine gold.
Just below this is 999.9, or “four nines” fine. American Buffalo and Canadian Gold Maple Leaf coins are made from this fine gold.
Most commonly, fine gold is 999. This is the gold most commonly referred to as 24 karat gold, although technically 24 karat gold is 100% pure. However, as this is difficult to achieve outside of a lab environment, 999 gold is generally considered close enough. Gold manufacturers are legally allowed a half-karat tolerance in making gold products. Fine gold of this standard is also known as three nines fine. It’s seen in Chinese Panda coins, for example.
Below this is 995, the minimum amount allowed in Good Delivery gold bars. Two nines fine, or 990, is rarely seen, but still technically a type of fine gold.
