I would love to see some sort of tariff or sanction placed on mined diamonds to make them restrictively expensive. There is simply no need for them any longer.
Step one - find a rare mineral that at this point has value close to zero. It is rare but worthless.
Step two - obtain monopoly on mining it or control it as much as you can (buy spots with dense occurrence, etc)
Step three - throw money at important and powerful people (such as Spielberg, so that in his new movie today's Marilyn Monroe is wearing your ore as a form of very high luxury) other media stars, politicians etc.
Step four - continue with excellent PR until enough wives or soon-to-be wives come to their soon-to-be husbands and request them to update their luxury status by buying your ore.
Step five - collect trillions of dollars across the globe, by tightly controlling your ore and its harvest.
Edit: step six - rinse and repeat for 50 years getting yourself even wealthier.
Maybe not exactly billionaires, but
If a man really wants to make a million dollars, the best way would be to start his own religion. :)
Various sports. Formula One, for instance, is the epitome of racing despite there being plenty of other ways to race cars.
Bottled water. Competes with a spout that everyone has several of in their home, yet people still pay up for it.
http://www.cc.com/video-clips/acaxis/key-and-peele-the-heist
It's a skit by Key & Peele describing a genius plan for a bank heist. I won't ruin the punchline by going any further.
If they had to hand it over to the Customs Officers those holes would suddenly be less attractive.
Or, modify the growing process so that it has a greater element of chance to it? (this is likely multi-dimensional)
A diamonds primary value is the history of it's making. People are unfortunately always going to be paying more for a diamond which has been digged out by hard labour than created in a lab.
Keep in mind the value of diamonds is mostly a perceptive one. I am pretty sure if you only did synthetic diamonds it would soon fail to be valuable as the "womans best friend"
Sure. On the other hand, if the synthetic diamonds were the flawed ones, you'd be saying "not everyone will settle for imperfection".
Really, diamond is one of those stones where it is the less true. Partially because of brilliant marketing, partially because in such a tiny clear stone the effect is mostly to dull it (speaking of it physical characteristics, not the emotional response).
That is not the case in Rubies or Sapphires. Emerald is meant to have imperfection.
So you went with a "natural" N/I1/fair?