From at least one man's perspective, it is given a lot more importance than it deserves. Tauriq Moosa wrote his views on the expectations for an engagement in "A man's perspective on why engagement rings are a joke" He declares:"They're expensive, useless and, worse, are insulting to notions of actual love. As anyone who's been in a serious long-term relationship knows, you don't need geology to proclaim (let alone justify) said love."
Much of his argument relates to the construction of the diamond engagement ring standards, which were part of the most brilliant marketing campaign every conceived by Madison Avenue. While the earliest reference to diamond engagement rings go way, way back to 1477 when the Archduke Maximillian of Hamburg gave Mary of Burgundy a diamond betrothal ring, the expectation for every bride-to-be to get one has much shallower roots.
The “tradition” of giving diamond engagement rings only became firmly entrenched in the 20th century as a result of a hugely successful marketing campaign by the DeBeers conglomerate, which controls the largest share of the world’s diamonds. When demand for diamonds sunk to an all time low as a result of the Depression and the World War II, De Beers and the N.W Ayer advertising agency came up with the”A Diamond is Forever” slogan. The slogan worked so well that the diamond solitaire became the paradigmatic engagement ring.
To further bolster the diamond market demand subsequent ads by De Beers convinced people to keep their diamond jewelry as cherished heirlooms. It was not sentimentality they were really encouraging but an elimination of recycling diamond. Without people selling the diamonds in their possession to be set in new rings, the demand for new diamonds remained strong, as it does today.
recent years, the diamond industry focused its attention on increasing the demand for diamonds too small to form the center of an engagement ring. The result of its efforts is the popularization of the 3 stone setting for an engagement ring in which the central solitaire is flanked by two smaller diamonds. The smaller stones are supposed to represent the past and future that surround the brilliant present. To promote the really small stones that are usually the byproduct of cutting larger ones, jewelers offer “eternity bands” set all around with very small diamonds. These bands are intended as the perfect anniversary offering. But for the manufacturers, they are the perfect solution of what to do with all the diamond chips too small to be of much account in jewelry.
So there you have it: it's all a matter of drumming up demand for the supply -- basic economics and rather sophisticated marketing. Certainly, there is nothing in Jewish law that requires a diamond engagement ring. The only ring needed is the plain band that one gets under the chuppah.
Unfortunately, we're all caught up in societal expectations, and that includes diamond engagement rings. While the bride-to-be can make it clear that she'll do without it, the groom-to-be is expected to offer it. I've heard of engagements that were broken over the issue of the ring. It's really sad, but that's the reality of society today.
Related articles http://www.examiner.com/article/tradition-versus-traditionalesque