LOL sorry guys and gals I think I might have spurred this thread as I stated in another post that Mach Five seemed like the kind of person who would opt for a Cubic Zirconia instead of a real diamond due to his "frugal" nature.
I think one of the articles that might have "inspired" Mach Five on this would be the following link at the atlantic:
http://www.theatlantic.com/issues/82feb/8202diamond1.htm
Sorry Mach didn't see you beat me too this link and that you *just* noticed it, you would think that someone as enthusiastic about the diamond industry would have read this ages ago as I did since it was written in the early 80s and all...
This is an article that touches on many of the issues that Mach brings up, however it is rather dated seeing that it was written in 82 I believe, and I also find it rather humerous that they predicted the collapse of the diamond cartel/empire however here we are more than 20 years later and I have yet to see anything of the sorts come about.
Also interesting to note is exactly how many industrys back in the day were wrought with shadyness, manipulation, and also underhanded business practices..especially the oil industry as someone so aptly pointed out however I think it is safe to assume that Mach Five isn't driving an electric car especially since he was recently arguing the merits of the performance that front wheel drive cars have to offer, and seeing as how electrics are the antithesis of performance...well you get the picture.
Are diamonds rare? no
Are diamonds worth what they tell you from a practical standpoint..never, they are a luxury item and in high demand thus they are expensive and you don't get alot in return.
Are diamonds better than synthetics? well, depends on what you are looking for and what your sig other is looking for
And For all those out there who suggested getting a fakie and trying to pass it off as real, really not a good way to start a relationship, plus the ring is more than just a monetary symbol, it also shows that you are willing to work for something that your sig other wants and that you feel symbolizes your bond, if neither of you feel that this is important then no one is twisting your arm to buy one.
Mach Five said in another post:
If I ever meet someone I'm serious about entering into marraige with, she'll be the kind of person who doesn't give two sh!ts about a price-inflated rock on her finger, but about the sentiment that the ring is given.
To which I say, good luck....like it or not the masses have embraced the concept of the diamond ring as the standard for engagements and weddings, and many women do like the look of them a great deal, sure marketing and market manipulation may have played a significant part in this, but you can market an ugly thing all day long and it still won't sell, there has to be some draw outside of the marketing for a product to truly become popular.
So sure, you can hold out and try and find the *perfect* significant other that shares in your hatred or distaste for the diamond industry, or even better you can try and train whomever you are with to hate diamonds as much as you do...all I can say is good luck

if my fiancee likes the look of diamonds I am certainly not going to spoil the fun for her that is for sure.
Look at the article I posted, this is obviously nothing new yet people still want diamonds, heck they are growing in popularity not only in the US but also world wide, heck they have been the industry standard for Weddings/engagements for almost the past centuary.
Also I agree with many who say you can try and convince your sig-o about how awful you think the industry is but in the end it will still be about what they like/want...
Sorry to keep editing this but there are two ways you can look at people like Mach Five....
1. he really cares about the well being of society and that this is something he is generally enthusiastic about, something that gives meaning to his life, fighting the evil debeers cartel that is...
or more realisticaly
2. he is trying to justify his "cheapness", he has already posted negative comments about more than a few high priced items on the boards (Sunglasses and German autos), heck why not follow it up with a nice slam on Diamonds too since they are highly expsnsive and seen as the benchmark for high end luxury purchases...
I am curious to know Mach exactly what precious metal or stone do you think "serves a purpose"? you state that Diamonds have no use other than "looking good" whereas Oil is used to power, heat and other various uses, however you seem to forget there are many diamond tipped drills

...and exactly how do other precious materials fall into place in the grand scheme of yours as being "worth it" what practical purpose do gold, platinum, rubies, emeralds and the rest really have? I am anxiously awaiting your response....