Valentine’s Day was last week and from inside sock drawers around the world, men (and a few women) produced rings intended to convey their everlasting love. Since De Beers, the world’s leading diamond company, ingeniously announced that “diamonds are forever” in the 1940s, most engagement rings have included a diamond—and an expensive one at that. The average American will spend $5000 on the band for their proposal.

A lot has changed in recent years, however. The most important development is the soaring popularity of lab-grown diamonds. Identical to their natural alternatives – except to gemologists with specialist equipment– such stones now make up about half of the American DER [diamond engagement ring] market, says Martin Rapaport, chairman and founder of Rapaport, a diamond pricer, up from a tiny fraction a decade ago.