It's thought that the ancient Romans introduced the tradition of wearing the ring on the third finger of the left hand. This finger was believed to contain the "vena amoris"—the vein of love—which was thought to lead directly to the heart. The tradition of the diamond engagement ring goes back to 1477 when Archduke Maximillian of Austria gave a diamond ring to Mary of Burgundy, as a token of his undying love.

The value of a diamond is ultimately determined by Four Cs:

CUT: refers to the arrangement of the diamond facets. Common cuts include round, oval, brilliant, marquise, heart, pear and emerald.

CARAT: refers to the weight. A carat is 200 milligrams, with one carat made up of 100 points. In other words, a 25-point diamond weighs a quarter carat and a 50-point diamond weighs a half carat.

CLARITY: refers to the way light is reflected through the diamond. Most diamonds have flaws, called inclusions, which affect the clarity of the stone. The fewer flaws there are, the more brilliant (and the more expensive) the diamond is.

COLOUR: most diamonds have subtle yellow or brown tones. Colourless diamonds are more rare and therefore more valuable.

Some couples have adopted a family heirloom as an alternative to the diamond ring. Also, gold from old rings no longer worn by family members can be redesigned into a special wedding band. If you use a ring designer, be sure to discuss your taste and lifestyle to ensure that a complementary ring is created.