Platinum is currently my most popular metal for engagement rings. It is extremely durable, hypo-allergenic, and is prized worldwide as the most valuable jewelry metal. It is the most difficult and exciting precious metal to work with, but customers who make thier own engagement rings out of platinum have had the highest level of satisfaction.
Many people associate platinum with diamonds. This is because it's durability make it the best choice of metals for prong-setting valuable stones. If you want to design your own engagement ring - especially if you will prong set a diamond - I encourage you to consider platinum.