Quote Originally Posted by http://en.wikipedia.org/wiki/Engagement_ring#_note-0
The diamond engagement ring did not become the standard it is considered today until after an extensive marketing campaign by De Beers in the middle of the 20th century, which came to include one of the most famous advertising slogans of the 20th century: “A Diamond is Forever”.
When I do eventually buy an engagement ring, I'm fairly sure it will not be a diamond. Diamonds, in particular, carry a history of human exploitation, and are far overpriced due to artificial scarcity. There are plenty of precious stones that are inherently just as valuable as diamonds, without all the baggage.