Traditionally in the west , an engagement ring is any ring, plain or diamond and gemstone set , that is worn on the left-hand ring finger indicating a womans engagement to be married. It is conventionally accepted that the ring is presented as a gift by a man to his fiancee during or directly after she accepts his proposal of marriage. It represents an agreement to get married at some point in the future.

This tradition apparently dates back centuries to an early usage reportedly referring to the vena amoris or "vein of love" on the fourth finger of the left hand.

More recently it has become common (although still rare here in the UK) that a woman will also present an engagement ring for the man. In Scandanavian countries both the man and woman wear engagement rings. However, the man's engagement ring is often used as his wedding ring too.

Engagement ring designs have varied greatly over years. Typically the band will be made from either gold or platinum and be mounted with a precious gemstone such as a diamond, ruby, emerald, sapphire or other gemstone. The Tiffany solitaire is probably the most common style sold nowadays, due in part to the Debeers "A Diamond if Forever" advertising campaign in the 1940s. The diamond engagement ring is now well and truely established as the standard in western culture. The modern engagement ring is intentionally expensive, most likely the symbolism of how committed the man is. The explanation for the diamond is that it is the most beautiful and enduring gemstone known to man. Some people prefer other coloured gemstones such as sapphires and rubies, which are almost as hard as diamond. Emeralds, Opals and Pearl are used too but not as often as these are softer stones and not always suited to the wear and tear of everyday use.

In some scandanavian countries the engagement ring is a simple plain gold band without any gemstone at all. Whilst in France, it is the norm to mount the engagement ring with a coloured stone in preference to a diamond.

Platinum is usually recommended by fine jewellers nowadays, not only because of its rarity and higher value, but because it is much more durable than gold, its naturally white and is less likely to cause an allergic reaction. Often a gold ring will feature a platinum head setting because it offers better protection fot the stone.

In contemporary engagement rings, Titanium and even stainless steel is becoming popular because of lower cost and high strength. Although these metals lend themselves to the tension setting style because they must be milled on a lathe. The temperatures required for proper hand fabrication would be far too high for most fine jewellery workshops. A titanium ring could also be dangerous were it necessary to remove it in the case of an emergency, because a typical hospital would be unable to cut though most grades of titanium.

At one time, engagement rings were mounted with different sets of stones to celebrate the joining of two different families: The birthstones of the bride's parents and/or bride, and the birth stones of the groom and his parents. These token rings often had hidden compartments where a lock of hair could be retained.

A Victorian tradition was the DEAREST Ring, where different gems were used which spelt the word Dearest using the first letter of every gem (such as diamond, emerald, aquamarine etc).

The first ever recorded diamond ring was presented in 1477 by Archduke Maximillian of Austria to Mary of Burgundy, However, the diamond engagement ring didn't become the standard it is considered these days, that didn't happen until a highly successful advertising campaign by the DeBeers in the 1940s