Sterling Silver Purple Stone Amulet

This is my newest piece, and I think it is my favourite. It caught my eye in a tray of various older silver pieces. No idea where it came from, what influences the design came from, or what stone is in it but I just fell in love with it and couldn't leave without it. It is all hand carved; under a 30x loupe imperfections in the design are evident, along with barely visible tool marks inbetween the cut outs. The 'waves' along the edge of the circle are not at all consistant with eachother. It really is the imperfections I love about the older jewellery though, you can tell someones sweat and blood went into it. Old fashioned bezel setting with bordering rope for the gemstone; it is an absolutely stunning cut, I'm thinking it's amythest but has a tanzanite like colour. Almost periwinkle, but a little more grey and purple.

Any thoughts on where the design came from? My first thought was Celtic, then I thought maybe Asian instead, but the more I look into older jewellery from those two cultures, the more I think it is Celtic.