Rings have been worn in Eastern and Western cultures, by both men and women, since they were first introduced in the third millennium BC.
These two rings are a clear indicator that it is not just the carat (or weight) which determines the price of an emerald - the color, clarity , and cut of the stone are also important. 

So while the ring on this page, which is made from platinum and is set with a cabochon emerald weighing 4.48 carats in a pave-set and baguette-cut diamond tiered surround, the cluster ring opposite, which features a cabochon emerald weighing 17.33 carats in a circular-cut diamonds two tiered.