You can look through some of the long time members' posts here and see that their ashas have not clouded. The fact that they are still here and are buying ashas attests to it's durablity and wear. As for scratching, it depends how hard you are on your ring. Diamonds and all sims will scratch if you ding them just the right way.
I baby all my rings and so far, all my ashas are pristine!
"Lucky I'm In Love With My Best Friend" - 21 wonderful years on 11/13/14! I love my kids!