According to popular opinion, Silver is deadly to Werewolves. In recent years, it’s been thought that it’s also harmful to Vampires, as well.
And as I remember, Iron is supposed to be harmful to fairies and Elves.
My question is…Is GOLD supposed to be harmful to any supernatural creature? Or Electrum, for that matter?
Well, thanks for your patience for my silly questions,
Ranchoth
Gold can temporarily halt the terrible rampage of the Greedy Little Slut. But the effect IS only temporary. 
As all Dr. Who fans know gold is fatal to Cybermen. Not sure they qualify as supernatural though.
Well, the myths of things that required silver and iron to kill were from a time when both metals were expensive, but available to the common classes. I would take some severe stones to even claim that they had used a golden anything to hit pixies, or throw at gnomes, or whatever.
I think a golden sickle is featured in some myths, but only as a sacred implement for ceremonial use.
Tris
As far as warding or directly harming supernatural creatures, I’m hard pressed to think of any. As a matter of fact, I seem to recall several creatures being so fond of it that one would do just as well trying to defeat a hungry lion by tying a rib-eye to your ass and shaking it at him.
But there are several creatures whos greed can be played upon with a few nuggets whic would draw them into a trap the well intentioned hero could spring, leading to their ultimate demise.
Dragons seem to be notoriously fond of the stuff, along with other treasures, and would storm from their lair burning all kinds of thatched roof cottages and generally raising all kinds of a rukkus. Smaug from the Hobbit, although he was not intentionally drawn to a trap, was one of these ill fated lizards. I think it is a trait that tends to be more prominent in the European dragon as opposed to the Asian one.
I’ve read several references to the fact that if you snag a piece of leprachaun gold, he will be at your mercy. This generally tends to lead to all sorts of not well thought out consequences, which generally ends up with the snide little bastard skips off into the sunset with his gold back while the poor tricked peasant is stuck back where he started with a crabby old wife and a shack not fit for a third world country.
Mummies also don’t seem to be too fond of having there gold swiped, and sometimes there is a curse associated with it. You may recall fond memories of a mummy lurching after Scooby Doo grunting “Coin! Coin!” I do not recall whether or not the coin of subject was actually gold, but then again, most mummies just seem to be generally ticked off about the breaking and entering, with the gold swiping as an afterthought.
I recall reading some piece of literature once that said the Kappa of Japan had an aversion to gold. That could also have been a method of appeasement, but since I can’t find the reference, I’ll leave you with the thought.
As far as vampires go, there are so many different varieties (check Cecils article about the best methods of doing them in) that I’m sure if we dug deep enough, you’ll find some obscure blood-sucker who isn’t too fond of getting within a hundred yards of ol’ king Midas. I’ll be doing some searching after this post for you (I have quite the hefty supernatural library, and it’s going to take me awhile to wade through it)
Now, to pose a little extra question on top, I always wondered about this in a biblical sense. Gold seems to be thought of as a Heavenly metal in more than one school of thought, but in all the references I’ve read about demons, they can’t seem to get enought of the stuff. Although referencing the Lesser Keys of Solomon, now that I’m fliping through it, alot of talismanic magic seems to specifically suggest you make gold talismans and inscribe the names of angels, or several names of god and the demon can’t touch you.
Anyways, hope this helps for now. I’ll get back to you later, hopefully with some links from some of the books I find references in. But for right now, other than pissing them off, I think you’re not going to be in good shape if you threaten ol Dracula with that gold cross earing you bought in the 80’s.
According to Scott Cunningham, gold has long been believed to have generally protective properties, but he doesn’t list anything specific that it protects against or harms.
At one point a cup made of electrum was supposed to warn against the presence of poison. Again, no info on any specific anti-supernatural properties.
Interestingly enough, Cunningham mentions a Chinese tradition that Dragons fear iron.
Not exactly what was asked, but gold kryptonite will permanently erase Superman’s powers.
I always wondered how he found that out. There have been many “imaginary” / alternate universe stories where it happened, but how did the Superman of the mainstream DC Universe find this out?
I don’t believe Silver was supernatural. He was just the Lone Ranger’s horse, if I am not mistaken. A nice horse, but a mortal horse. 
I don’t know how recent the anti-vamp powers have been attributed to silver, Stoker’s novel DRACULA has vamps deterred by silver. The Universal WOLF MAN films extended it to werewolves (probably also because silver is the ‘lunar’ metal while gold is solar).
There is the white gold from Steven R. Donaldson’s Thomas Convenant universe. That seemed to have considerable power against the baddies.
Thought experiment: Take ten tons of gold. Drop it on supernatural creature. Examine result. Check off “yes” on “Does gold harm any supernatural creature” question.
Many mythological commentators suggest that the “iron is dangerous to fairies” myth derives from a folk memory of conflict between ancient tribes who had iron and those who did not. Iron would certainly have been dangerous to them in the form of iron tipped weapons going up against stone spears and arrowheads. Note that well made bronze weapons are just about as good as badly cast iron, but one of the advantages the discovery of iron smelting brought with it was comparitively abundant and cheap material for metal tools and weapons, as you suggest.
I cannot think of any actial mythologica/legendary instances wherein gold in anathema to anything supernatural. However, in White Wolf’s Werewolf RPG, the Corax (wereravens) and the Mokole (werecrocodiles/weredinosarus) are affected by gold- it being the metal of Helios, which they are associated with, as opposed to most shapeshifters, who are associated with Luna.
But why waste 10 tons of gold in that manner while 10 tons of rock could do the same things? 
Because using gold is more stylish, and style always trumps substance.
Cheap gold-plated jewelery used to turn my stepmother’s fingers green, and I consider her about the same as Dracula or the wolfman.
The most horrible of all “supernatural” creatures, just a touch of a gold ring and it dies …
“Magical words, formulae, incantations, and amulets were thought to be curative. Styes could be removed by recitation of the rhyme “Sty, sty, leave my eye; catch the first one passing by.” Rubbing them with a gold wedding band would also work”
There was an episode of the old “Transformers” cartoon show in which the Decepticons gained access to a huge pool of electrum. Since Transformers become invulnerable if they coat themselves with electrum, they start kicking the Autobots’ asses until the Autobots grab some as well.
Kal-El knows because he saw the effects on Quex-Ul, way back in 1962, when Quex-Ul, after his release from the Phantom Zone, attempted to lure Superman into a gold-K trap but threw off the mental control of Rog-Ar at the last moment and sacrificed himself in the trap instead.
I hate myself for knowing this.