Index finger, where I wanted to wear the ring, was sized with official jeweler tool (separate ring for each size). The US 10.5 slid off too easy while the US 10 grabbed the knuckle well, so I settled on your size 20 which per your chart is US 10.25. The ring you sent is much tighter such that your size 10 is more like a US 9.5. That said I cannot wear in on the index finger intended, and it will only fit on the 3rd standard ring finger. In addition, the writing on the ring is less pronounced (visible) than the picture on your website, so you have to get up close to even notice there is writing. I thought about returning it, but will keep it after all as it was not too pricey, at least fits one of my fingers, and is a pleasing reminder of my time with Thoth on Undal before the flood.

Emerald Tablet Ring