1/2" Diameter makes these a very wearable size for every day wear, and in the medium size range for good visibility without being heavy or too small. Note that there are several matching pendant options as well. 

This design is seemingly whimsical, yet indeed ties into the very fabric of Celtic life of old.

The Solar and Lunar cycles are the natural time piece of the Celts. The winter and summer solstice/equinox alignments were very important for timeframes for specific activities, and the mid points between those solar junctions were the celebrations of the largest of Celtic ceremonial festivals. In the case of the Lunar Cycles, the elder women of the tribe, having seen life in all its phases, were honored with the planning and timing of important life events around the moon's ebb and flow.