Let’s say I figured out how to turn an orange into real gold. I start selling my gold oranges in the open market, become a billionaire, report my profits and pay my taxes. Are there any laws against this? Would they use some loophole somewhere to seize my method and throw me in jail? I can’t imagine that I’d simply be able to continue to make my gold once someone found out about it.
To the best of my somewhat limited knowledge, there are currently no laws against turning oranges into gold, so legally you are in the clear.
Realistically, your ass would disappear within manner of hours of a hint getting out that it was possible. Our government, some other government, some company…tag, you’re it.
FDR’s head in a jar would track you down and kill you.
No, it’s not illegal.
Now, there might be some technicalities and there will certainly be lots of legal hurdles. For example, if you’re using caustic chemicals, OSHA may talk to you. If you’re dumping those caustic chemicals, the EPA may talk to you. Someone may accuse you of violating their patent on techniques for fruit transformation. My state requires licensing for any business using weights/measures and you would certainly require that. Gold probably has laws requiring that you determine the purity.
Eventually, you’ll have protesters in the street, comparing your gold to GMO food. They might get laws passed that insist that your gold is not real gold.
But you should already have your billions by then.
There’s precedent for what you’re describing. Aluminum was a precious metal until the Hall-Héroult process was invented in 1886 and the price plummeted.
Say you come up with a cheap way to extract gold from seawater. There’s nothing illegal about that. You’d probably make a killing for a short while as you ramp up production and then the price of gold would settle down to a new value that’s much lower than it is now.
Effects on the world economy would be relatively minor. The days of the gold standard are long gone.
Why would the government care about mass producing cheap gold?
Not about the gold specifically but they’d be concerned about the economic crisis caused by a sudden plummet in gold prices. Whether they’d take illegal action to prevent it from happening depends on how cynical you feel about the government.
I’m guessing it wouldn’t be illegal until someone with a vested interest (and a lot of money) decides to force Congress to pass laws against your new gold.
ETA: Are there any laws against creating synthetic diamonds? Isn’t that a relatively new thing?
They’d probably be very concerned that the technique might also allow the mass production of certain other elements, like plutonium.
Why would that cause an economic crisis? Gold is not a very big part of the US economy. Gold mining would be pretty much wiped out, but there’d be a new industry in gold manufacturing to take up the slack. Other than that, who cares about the price of gold? Jewelry makers wouldn’t be happy. On the other hand, electronics manufacturers would be thrilled. There’s probably be a brief consumer fad in having unlikely objects made out of gold, but I don’t see any major economic dislocations coming out of this discovery.
It’d shut the goldbugs up at last, so there’s that advantage.
If the procedure can work for other elements, then you’d be wasting your time making gold. Sell the process for making cheap plutonium to the government, and buy yourself a couple islands to retire on. If you can do that, however, you’re well on your well on your way to Star Trek style matter replicators, and a post-scarcity economy, and the ramifications of that are huge.
Didn’t they just figure out how to manufacture diamonds in the past few years? Not by alchemy, but I hardly think the method would matter so long as it was economical for the producer. Has that been made illegal, or been restricted?
Think of all the nutcase gold hoarders out there. They’d go even nuttier. And they’d need to find something new to hoard when civilization crumbles, or the Rapture starts, or whatever.
And those people vote!
Yeah but the price of oranges would soar. No more mimosas. 
The price of gold per ounce may drop, but the total global value of all of the gold in the world would remain the same, and a greater portion of that total would be in the United States. That would be a good thing, wouldn’t it?
It would be the Post-Economy Age. I’d copyright the term, but what would be the point?
Why in the world would a new method of producing inexpensive gold cause massive economic dislocation? Yes, the price of gold would fall dramatically with the new influx of gold into the market. So what?
Falling prices for a commodity are a good thing, they mean that the good or service is more abundant and it is easier for people to afford it. Would we be better off if steel were more expensive?
Of course you won’t be able to sell solid gold oranges at current market prices for very long. Law of supply and demand, if you inject a large supply into the market and demand remains the same then the price falls. Of course at the new price lots of new applications for the commodity become affordable, so that increases demand again. The commodity finds a new equilibrium. At a low price point we can start making electric wiring out of gold instead of copper, the unique physical characteristics of gold make it a very useful material for all sorts of purposes.
One example off the top of my head, they’ve banned lead bird shot because of lead toxicity, but gold shot would work much better than steel shot and be much more effective and gold is inert and harmless. So duck hunters will be happy.
This is assuming the process is limited to oranges to gold only, and that further research won’t lead to further cheap transmutation. If it becomes trivial to synthesize plutonium, or polonium, or other radionuclides, then we can expect a massive wave of nuclear terrorism that leaves most of the Earth a radioactive wasteland.
Manufactured diamonds have been around for quite a while.
Until fairly recently they haven’t been economical to produce gem quality diamonds but that’s now possible. The prices for synthetic diamonds are lower than that of natural but that’s mainly marketing. The market has worked things out so far and synthetics will take over more of the market over time.
Before 1968 the government would have insisted you account for every gram of gold you produced and mandatorily sell your entire production to the government at the fixed price of $35 per troy ounce; perhaps that’s what you’re thinking of.