The Kimberley process was created to try and stop conflict diamonds.
Conflict diamonds fund mayhem, terrorism, civil war, and general brutal abuse of humans in a quest for power. Conflicts all over the world are funded this way.
Governments worked at 'cleaning up' the trade in diamonds where conflict diamonds were mined. They developed The Kimberly Process, whereby stones are certified as being conflict-free.The Kimberly Process is not per se, a social policy, but it is a government policy employed nearly world-wide based on conflict diamonds and their power to inflict death and destruction on societies.
Being able to identify minerals is like being able to identify diamonds from quartz--The person that makes the right choice is rewarded financially. Correct information is the kingpin of mining.
Diamonds are not necessarily disappearing. Diamonds are being mined all over the world, every day.
There doesn't appear to be any active plan or program to conserve diamonds.
Diamonds
All other measurements being equal, two diamonds of the same clarity, carat weight and cut, one being white and the other being brown, you'll pay more for a white diamond. Brown diamonds are the most common colour of diamond found, and one shade of this colour is called chocolate.
Truly, diamonds are everywhere. Above ground, you can find the 20% of mined diamonds as gemstones in jewelery stores and being worn by humans. The remaining 80% of mined diamonds -- industrial diamonds -- are in use as enhancements to tools. As well, since diamonds are formed below the earth's surface, there may be many more unmined diamonds there.
'Expensive' diamonds are only available in about 20% of all diamonds mined, the remainder being industrial diamonds. Of that 20%, only a few stones are large enough, clear enough, colorful enough or flawless enough to be sold as 'expensive' diamonds.
'Wasting' diamonds is not as much of an issue as losing diamonds. One looks after a diamond by securing it, keeping track of it, and when not being worn, keeping it in a safe place.
According to Wikipedia, the Dresden Green Diamond, the most famous green diamond, owes its "...unique apple green color is due to natural exposure to radioactive materials..." Some green diamonds are made more green after being irradiated in order to enhance its colour. This process treats or enhances a diamond, and therefore, makes it less valuable than a naturally coloured diamond. A certified gemologist can identify such diamonds.