Each finger had a symbolic association or meaning (most of which were lost in antiquity and varied with culture) for the placement of a ring, significant to observers. The fourth digit or ring finger of the left hand has become the customary place to wear betrothal, wedding and moissanite engagement rings in much of the world, though in certain countries the right hand finger is used. This custom was practically established as norm during World War II. http://www.asejewel.com/ring/moissanite-engagement-ring/