Most native metallic gold runs from 18K to 22K (750%-916%). In my mining experience doré bars smelted. From microscopic ores are usually lower. The reason for this is the presence not of. Dirt or rock but lots of other metals that are not removed in the fluxing process. These are usually silver and copper, but. Can include nickel, platinum metals and a host of others leached from the ore and added to the gold in processing. Alluvial gold mining is the process of extracting gold from these creaks, rivers and streams and is generally. Considered to be the most environmentally friendly method of gold mining as a result of the reduced environmental impact when compared to underground mining. Native gold nuggets and visible placer is normally of higher purity than metal. From leached microscopic sources. This nugget comes from the remote areas of New South Wales. Renown for having one of the highest naturally occurring purity gold reserves in the world. This is a must have for anyone looking to own a piece of New South Wales Australian Gold.