It is impossible to accurately examine or cut and polish a
stone without good magnification. We suggest using 10X or higher magnification
for faceting so you can see if all the fine scratches have been eliminated
Closing one eye, or squinting while looking through loupes can cause eye
strain. To reduce eye strain, keep both eyes open when looking through the
loupe. This may take a while to get used to, but it can prevent you from
getting headaches. After all, gem cutting is supposed to be fun.