An engagement ring has traditionally been given as a symbol of a man’s intent to marry a woman. When the man proposes to the woman, the engagement ring is presented. The way it is presented may vary, but it is always presented when the question is asked. If the woman accepts the proposal, the engagement ring is worn throughout the engagement as a sign that she is no longer “available” for courtship. Traditionally, the engagement ring is a gold or platinum band with a solitaire diamond atop it, however, it is not uncommon to see people using other types of rings or stones for their engagement ring. The wedding ring is the ring that is given to the bride (and one also to the groom) at the wedding ceremony. The wedding rings signify the eternal bond and sanctity of marriage. The wedding ring is usually a single band without any seam, although many wedding bands are decorated with stones or intricate designs.
In previous generations it was more common for the engagement ring to be purchased after the proposal. While it's not as "romantic," the bride has some input. Also, in previous generations it was much less common for men to wear wedding rings.