See @desertgem reply. It's impossible to perfectly replicate the conditions in a lab that create diamonds, it may be much harder to tell but there will be a way for very likely several lifetimes if not longer. Technology has a long way to go before it could replicate those conditions in a lab perfectly and even if it got there then you would assume that technology would also be good enough to know it was made in a lab. It would also have to be quick and profitable doing so in large quantities, if it was it would have been done already. But even if for the sake of argument they could, the real supply is so tightly controlled putting identifies in/on real ones would still separate them out.
The TV article got this wrong: "The only difference, even under a microscope, is laboratory diamonds have their certificate number inscribed on the side." Really it is this: " Just What Diamonds Have Serial Numbers? Not all diamonds have serial numbers. In the US, only diamonds that have been graded by the Gemological Institute of America (GIA) carry an engraved serial number. The serial number is engraved into the diamond as part of the certification process, and matches the number on the diamond’s certificate. In other countries, there are similar grading and certifying institutions that certify diamonds." http://www.dmia.net/diamonds-serial-numbers-3-reasons-want-one/ The problem is that the process of adding A Fake identity number is easier and cheaper than trying too hard to fool experts.
Which I am sure has been tried. When you really think about it simple chain of custody procedures would likely be enough given that they're a pretty one way market anyway if they couldn't come up with something better. Whatever they come up with I am sure that they will come up with something, there is just simply too much money on the line to lose that kind of empire without exhausting every possible solution
I can see the "What's It Worth" threads flooded with glass chips found on the sidewalk outside of the local tavern.
There's only one way to qualify what it will be worth. That's to professionally grade and appraise it - just like a coin. Diamonds - like other PM is traded as a commodity in many places - but there is a lot of speculation, and of course fakes and quality issues. A currency based off of them to me is irrelevant - we have the US Dollar and it isn't going anywhere. So diamonds to me are just another store of US value. This was my big score last year. Bought a ring at an estate auction. Pulled the diamond and had it re-cut, polished, certified, laser inscripted with a serial number, and appraised. I courted a few diamond brokers and took the highest bidder.
Diamonds are quite common. Without the artificial rarity created by the -edited- diamond syndicate in Antwerp hoarding them and handing them out as they see fit the market would be flooded.
But gold is fungible, 1 oz of 999 fine gold is exactly the same as any other oz of 999 fine gold. That isn't true of diamonds, every one is different (At least until the labs can make them consistent and identical. Imagine using coins where every coin has a different and varying value. And I still wonder what happens when lab grown gem quality diamonds become common place in significant quantity? Sure some collectors may desire and pay a premium for natural stones, but will they pay thousands for a smaller lower quality natural stone, when a larger higher quality flawless one can be had for much less?
Another problem is an ounce of gold can be fractionalized into smaller units without loss. A diamond cannot.
The technology for making fake diamonds is getting better and better. Soon they will be indistinguishable and the price of diamonds will crash. Diamonds are actually very common, but De Beers is putting tight control on the value of diamonds.
There are NCLT coins with diamonds. But can you imagine if they did circulate? They would scratch all the other coins that you have! At the same time, while diamonds are extremely hard, it does not mean that they are shatter proof. At the same time - I'm certain there have been enough stories of diamonds falling out of mounts.