Dealing in gold jewelry is different than dealing with pure gold. The gold found in jewelry is melted/bonded with other metals to make it stronger. So just because it may say 10 or 14k doesn't mean it is entirely pure gold. That's why they only give you so much a gram for it. The refinerys have to melt and separate the metals to get the gold out of it.
Raw gold like you find prospecting is at a much higher value anyway. It comes out of the ground around 22 to 24 karats and really doesn't have any impurities. Gold prices are up there right now but just hold onto it. The buzz in the prospecting world is that it will be over $1,100 an ounce. When I first got into prospecting last year it was just $600 an ounce.