Diamonds have been known to hold intrinsic value for 1000s of years and there is no indication that it will
change in the near future. Obviously its a lot to do with people perception, as if people will stop consider
diamonds or gold valuable, it will lose all its appeal, but lets face it its not going to happen simply because humans
always need some asset of intrinsic value in times of crisis, inflation, as diversification of their investment, etc.

As for monopoly, its a quasi-monopoly where prices are controlled by few, so in this regard value/prices are unlikely to
drop as it will simply mean no profits and bankruptcy for companies involved. In this situation investors are more
safe, as market is not likely to fluctuate a lot due to speculation.