Diamond is the most beautiful, precious, concise form of material possession that its owner can take pride in. It is rightly said to be the “BIGGEST VOLUME IN THE SMALLEST VALUE”.
This is probably why diamond came to be used in engagement rings to begin with. The most precious material gift to tie the most precious immaterial bond forever.
In the British-American tradition, an engagement ring is a ring worn by a woman on her left-hand ring finger indicating her engagement to be married. By modern convention, the ring is usually presented as a betrothal gift by a man to his prospective bride while or directly after she accepts his marriage proposal. It represents a formal agreement to chastity and a future marriage. Similar traditions seem to date at least to the ancient Greeks, Romans, and Egyptians. In Rome it was believed that the "vein of love" was located on the fourth finger of the left hand. In the United States, it is more common today than it used to be for a woman also to buy the man an engagement or promise ring at the time of the engagement. In Brazil and Germany, both the man and the woman wear engagement rings. In some societies, it is traditional for the engagement ring to cost the equivalent of one month's pay of the man's wages. In the United States, diamond industry advertisements advocate two months' pay. A spokesperson from Tiffany’s Australia,
quoted on the television program A Current Affair (February 1, 2005), suggested that a man should spend two to three month's salary on an engagement ring.