IMO gold will be a common currency again, simultaneously with bitcoin. I know the "winner take all" theory is popular, but, well, it's wrong. What will change is the need for governments to stamp art on the gold because without debasement (taken away by bitcoin), there's no use for that art. People will use little gold pellets and have little handheld machines that vaporize the gold and run mass spectrometry on it to verify purity. The same machines will have built in bitcoin wallets and a QR display.
Discussion
No chance it will be common currency. Even now, a 10th of an ounce is worth $400. Do you know how small a 10th oz coin is? There's no one who will go into a grocery store and be able to spend that coin, and no store will have small enough gold to give change. Now double the value of gold and figure out how to make the necessary divisibility work.
Gold was never a common currency, for the broader population. They used copper, nickel, and silver.
If only we can figure out how to transmit gold over the wire.
The words "silver" and "money" are synonymous in several languages.
French: argent (both silver and money)
Hebrew: kesef (ΧΦΆΦΌΧ‘ΦΆΧ£) (both silver and money)
Irish (Gaelic): airgead (both silver and money)
Scottish Gaelic: airgead (both silver and money)
Welsh: arian (both silver and money)
Breton: arc'hant (both silver and money)
Manx: argid (both silver and money)
Cornish: arghans (historical use for both)
Well. Take into account #preciousmetalinflation which believe it or not will be a thing in less than a decade most likely.
Right now there is a finite amount on earth. But not for long. #spacemining will flood the market with gold, platinum and others. That will change the standard.
Of course, the mining companies can do the same as was done with diamonds. They are essentially just as common as quartz, just mined and hidden away to inflate value. #variables
I doubt it, but I think gold-backed transactions are making a comeback. You always need some second money for a conduit, tho.