Early 1940's: Engagement rings become the leading line of jewelry in most department stores.

1944: A Catholic priest queries The American Ecclesiastical Review as to whether he's permitted to marry a couple in a "double ring" ceremony, and, if so, how to go about it. (The Roman Ritual calls only for the blessing of the bride's ring.) The Review OKs the practice.

1946: Humphrey Bogart chooses to wear his first groom's ring when he is married—for the fifth, and final, time—to Lauren Bacall.

1950: Breakfast at Tiffany's is published. In Truman Capote’s novel, Tiffany's engraves the cracker-jack ring that winds up as Holly Golightly's engagement ring.

1978: Following her divorce from Richard Burton, Liz Taylor puts the 69-plus karat "Taylor-Burton" diamond up for sale to raise funds for a hospital in Botswana.

2000: Amid growing concern over human rights violations associated with their trade, the diamond industry creates the World Diamond Council to develop and oversee a tracking system that will "prevent the exploitation of diamonds for illicit purposes such as war and inhumane acts."

2001: Brad Pitt sues Dalmani International, which made the wedding ring he gave Jennifer Aniston. Pitt says the ring was his exclusive design, but the company sold replicas and implied the couple endorsed them.

2002: According to a Fairchild Bridal Group Study, more than a third of couples buying diamond engagement rings spend at least two months' salary.

2003: Wal-Mart introduces its "Keepsake" brand of diamonds and, according to its annual report, becomes "one of the top sellers of diamonds in the world."

2005: A week before Valentine's Day, the one-carat round solitaire diamond ring set in 14K white gold ($1,988) is out of stock on Wal-Mart.com. The author of this story notices a day-glo billboard in her hometown of Lincoln, Nebraska, advertising an "ENGAGEMENT RING EXPLOSION," and hopes no one was hurt.