Well, my first reaction is to explain that since you’re determined to buy a diamond, there’s no way you’ll get around being ripped off. Basically, you’re trying to purchase a crystalline mineral which is present in obscenely huge amounts in the earth’s crust. Unfortunately, there’s a cartel which controls the commercial supply of diamonds, making an artificially high price. Also, a large number of diamonds come from areas where guerilla or national armies use slave labor to mine the diamonds and then use the proceeds to finance more war. Diamonds do not increase in value, so they make lousy investments. They are basically a way to show off the fact that you have expendable income.
That being said, there are four major factors to consider in buying diamonds. They are the four C’s: Color, cut, clarity, and carat.
Color is pretty obvious - what color is the diamond? Some colors are highly sought after - like blue. Others totally trash the value of the diamond. For a person of modest bucks, you’d want to go for the clearest diamond you can afford.
Cut refers to the proportions of the diamond and how the diamond is shaped. Some cuts show off the brilliant refraction of a diamond more than others. If the cut of the diamond is too steep or too shallow, it won’t reflect light well, and the sparkle of the stone will be diminished.
Clarity is also pretty obvious. How clear is the stone? Are their flaws? Inclusions? Cracks? All natural diamonds will have some sort of flaw. The question then becomes how much those flaws detract from the stone. Many are completely unnoticeable. Others are extremely distracting.
Carat is the weight of the stone - how large it is. Used to be that a woman could be quite happy with a 1/4 carat diamond engagement ring. Now it seems like you can’t get by unless you’ve got two full carats on a platinum band. Shows you how successful the diamond cartel marketing is.
Canada has recently discovered some diamond deposits, and the mine owners are not members of the cartel. However, because they are conflict-free diamonds with a certain cachet, their prices aren’t much, if any, better than the others.
You might want to make a point of asking your wife what kind of gemstones she likes. The answer might surprise you. Me, I’m very fond of semi-precious gemstones and some of the precious ones like emeralds and rubies. Go that route, and you might find that you get more for your money, please your wife, and come up with a unique gift.
You can find more info on diamonds at: The Diamond Buyer’s Education