User blog comment:Merlin2Emrys/Morgana's necklace/@comment-5209013-20121129081926

It's a triskelion, a common symbol in pagan belief. The three spirals you see symbolise the ongoing circle of birth, life, death or - and this looks more plausible for Morgana as she's a 'High Priestess of the Triple Goddess' - maiden, woman, crone. The triskelion is the Celtic predecessor of the holy trinity in Christianity.

If you look closely, you can see that there is also another symbol included on her necklace (you can't really see it well on the picture above, but it is visible in HQ pictures). It's a triquetra, the Celtic symbol of feminine spirituality and the Triple Goddess.