Natural Catalina Iolite Platinum Over .925 Sterling Silver Ring (Size 5.0) TGW 0.720 cts.
Iolite is readily available and surprisingly affordable. The richer the blue, the better. It is mined in India, Sri Lanka, Mozambique, Zimbabwe, and Brazil. The Vikings probably mined theirs from deposits in Norway and Greenland.
Iolite is relatively hard but should be protected from blows.