This medallion is a representation of the relation between Pi and Phi golden ratios. You will find a full description of the history and the symbols of this jewel on my blog:
https://www.theosdoron.com/blog/creation-of-a-jewel
I have choosen precious materials for this first jewel, but you will find a series of copies more suitable for crafts in my shop. Please visit and subscribe to my website for upcoming updates:
http://www.thecarpenthours.com