This necklace holds the three goddesses. All of the sisters hold a psychic ability that is passed to you. The three sea glass stones are for their third eye. If you had a hole in your head you could pop it in and go, instead, you can hold or wear it. The reason there are three is that one is for the past, one the present and the last one is the future. All of these you can change. Sea glass was used because of the way water washes over it, the flow of time is represented here.
This supernatural piece of jewelry is very easy to use to open or get a third eye or just enhance your own psychic ability. The enhancement of your future or the changing of a terrible past is a plus. A little like your own time machine.