Aquamarine and diamond halo birthstone pendant is a great idea for any birthstone. Can be customized, & would be gorgeous with Amethyst, Topaz, Ruby, Sapphire, Peridot, etc. just to name a few.

The pendant seen below is 14K white gold, & has a March birthstone center, which is an Aquamarine. the pendant swings freely from the diamond baille. There are 47 round brilliant cut diamonds app. .25cts., around the halo, in the baille, & around the outside of the pendant. All the diamonds are set with common prongs for a dramatic look. The necklace can be any length.  18″ is probably the most popular.