I don't remember the name off hand but there was a jeweler that always advertised as being ones who charged you by the actual weight of the gold plus IIRC $50.00.
As for profit, in the words of Randy Savage "OOHH YEAHHHHH" Most finished jewelery has a HUGE mark-up for profit. Most places you hit are in the range of 300-400% of the wholesale cost of the finished item, which itself is usually 200 percent of the price of the materials and time used in creation. Some of the really "exclusive" places are even worse. Plus there are some big regional differences as well. The wedding band I wear is a simple diamond etched 14K item.
Distributor price on it was around 80 bucks when it was purchased. Retail in this area would have been closer to $200.00.
You might try posting this question on the rec.craft.jewelry newsgroup. The moderator there will answer your question and there are other knowledgeable people their to offer answers.
My recommendation is to go to a jewelry supply store and purchase a melting dish. They are made of clay, and not terribly expensive. It is VERY important that you season the dish before using. They are notorious for cracking when first heated, otherwise. Begin by heating the dish on a low heat, so the moisture contained within will evaporate slowly. When the dish has dried well, raise the temperature of the dish to a dull red heat (using a torch), then sprinkle a little borax on the dish, so it ends up with a thin coating. That coating will prevent the gold from sticking to the dish, and allow the molten gold to pour easily from the dish. Make sure the spout is coated. Too much borax and it pours off with the gold, so pay close attention to the amount you use.
Borax glass, or anhydrous borax is the best choice, but you can use any borax you can find, it just contains water and is light and fluffy, so it tends to blow away, unlike the anhydrous or glass borax.
A mold can be prepared by drilling through a piece of steel, although I think I'd recommend a piece of cast iron instead. The finish of the hole should be quite good, so the gold can't key. When the mold is made, it should be heated to dull red, to oxidize the surface, which will help prevent soldering of the gold when it is poured. Use a second piece of metal as a stop for the bottom of the mold. It, too, should be oxidized and then smoked well, to prevent soldering.
When you are ready to pour the gold slug, the mold should be preheated to a point just under 1,000 degree, then it should be fully smoked with an acetylene torch. The carbon film will serve two purposes. It will prevent the gold from soldering to the mold, and it should yield a thickness that will make the resulting slug a tiny amount smaller than the mold, so it can be removed easily.
That can be risky. What ever the choice may be, it must be resistant to thermal shock. Ceramics (Coors, for example) isn't. My previous post details what works very well, and has been used for years by the jewelry trade. I used the same system when I refined small lots.
That is absolutely the truth. Nuggets tend to be worth far more than the gold they contain. Anything above a troy ounce is usually in demand as a specimen. Small nuggets may or may not be worth more. I processed anything that came in that was small.
PURE carbon graphite yes provided it's yellow gold.
I would suggest an easy method myself. Involves less work and will give a good result.
Grab a carbon arc rod. Bore a hole slightly over-sized into it and 3-4 times deeper than needed. Now use nippers to cut the gold into small pieces and drop them into the hole. Grab a good torch (MAPP or O/A) then heat the rod until the gold melts. Add more gold as needed until you have a large enough piece. Let it cool and then us the nippers to cut/crush the carbon. You basically will be using the "crucible" as a disposable mold. Remove the gold and machine as needed.
"My recommendation is to go to a jewelry supply store and purchase a melting dish. They are made of clay, and not terribly expensive. It is VERY important that you season the dish before using."
Harold was referring to vitrified ceramics. We used to use 99.5% (iirc, that was in 1980) alumina Coors brick, we had about 300,000 of them in an experimental electrolytic cell. The heatup schedule took 6 weeks to 700 C. The cell was 75' x 30' x 7' deep. Those bricks were highly prized for sharpening knives. And they were very sensitive to thermal shock.
Check the Riogrande site again. There is a stock jewelry finding called a "Straight tube bezel w/bearing.". It is a short straight piece of gold tubing with a counterbored end for a stone to sit in. Assuming your opal is close to the diameter of the bar you inquired about, you need one for a .35ct or .50ct stone.
In that size they will probably only be 3-4mm tall. They will probably cost $15-20 each in 14k
My point, which I apparently didn't state, or you didn't get was that for the average layman to trade in gold is not as simple as weight x spot price equals value.
Hope I got it right that time. I don't know everything about gold, but I know a good bit about placer mining. From there, the refining and testing is up to the experts.
And most laymen are not experts, but are exploited by some of them, and the conmen, too.
I believe that the current wave of gold buyers on TV must be rolling in the dough. A lot of people probably send in diamonds and all, just getting paid for the gold. And I'm just a little bit suspicious as to whose gold they are sending in for fast cash.
Here in the old west, I have found assayer's shacks, or what's left of them with the remains of thousands of broken crucibles laying scattered all about.
Not quite sure of your reasoning, stating it must be yellow gold. To my knowledge, gold alloy of almost any description can be melted with a graphite vessel.
You are dead on with your assessment. People are being screwed by these buyers. KSL TV did a story on this some time ago. Cascade Refining, in SLC, was found to be quite honest with their customers. If memory serves, one of the mail-in buyers returned a miserably low percentage, something like 18%.
It's very difficult to deal in gold unless you are willing to take a bruising.
I know and understand that, but if you say ceramics and leave it as such, I think you'll find that enough people will not consider a clay dish as being satisfactory, when it is, and may even consider that Coors lab ware would be the best choice. If you've ever worked with any of that stuff, you know how it isn't fond of thermal shock, which is hard to avoid when working with molten metals.
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