People in the business of selling precious stones could care less about where or how they are obtained as long as the buyers get a good price. It's an old story told over and over throughout human history; whenever there is something of value, the rich will do whatever it takes to get it. Even if obtaining something of value results in the suffering and deaths of millions, the rich and greedy will pay with currency for that which was produced in blood.
The list of things to ban:
1. Monsanto's GMOs.
2. The entire diamond trade.
3. Products from endangered species.
Now it's your turn to add to the list.