If it’s not deep you can buff it out, even though it’s sapphire. You just need the one thing harder than sapphire - diamond!
So what you’ll want is diamond polishing paste. First you’ll need 2.5 or 3 micron to get rid of the scratch, then 0.5 micron for final polish. You can just use microfiber cloth. you can buy paste on eBay from China. I paid $10 for a set of pastes.
Will be more cost effective than crystal replacement, and if the scratch isn’t deep, will look as good as new