This is true when selecting a fancy colored diamond too. For instance, a yellow diamond in a yellow band will surely look dull. Ideally, one would want a contrasting look altogether. So you need to select a metal band that will complement the color grade of the gemstone.
Diamonds reflect light or any colors that directly surround them, comprising those in your ring setting. If you are planning to choose diamond rings and gold bands, also think about the purity of the precious metal. Of course, 24 karat gold is the purest of the lot. However, most jewelers use alloys, which in simpler terms mean less gold karat.
The higher the gold karat, the softer it is. Thus, for everyday wear jewels, the 24 karat gold is not necessarily ideal. It is good to choose 18 karat gold, though 14 karats will be more ideal for everyday wear.
Allergies are relative, though it is one factor that should be considered also. It is pointless to select any type of gold alloy, which contains a mixed material that causes allergic skin reactions. Experts say that nickel causes allergies; although the gold metal band with nickel traces comes with a rhodium plating, it will wear out over time, and if not re-plated, the skin will come into contact with nickel, thus causing allergies.