When my wife and I decided to get married back in 1994, we were still paying off student loans and car debts and the general detritus of university and early working life. We couldn't afford a traditional diamond solitaire engagement ring, so instead we bought a much less expensive set of matching blue-and-white sapphire rings (you can see mine on my right hand in this photo).
Also, I was a bit cynical about diamonds, with the whole De Beers cartel advertising campaigns, conflict diamonds, and so on. Conflict-free Canadian diamonds were not yet a force in the market as they are today (with a bit of their own controversy).
We have a bit more money now. Like a convertible sports car, a nice piece of art, or yet another guitar, a diamond ring is not a rational purchase, nor should it be. Yesterday the kids and my wife and I went to the mall and visited several jewelers, and she found a ring she loved, with a certified Canadian diamond. So we bought it. It was a good choice.