Just the affected area. You shouldn't worry about overpolishing. Saphire is really tough and using a dremel (which I did) carefully won't do any harm..Just polish on and a bit around the affected area and stop as soon as you see the scratch is gone..
Guillermo
Originally Posted by Mr Tetley
Ok, if I try removing these very fine ‘scratches’ should I just polish the affected area or should I polish the entire surface of the crystal? I’m considering starting with 0.25 micron diamond paste since they are very very fine.