Saturday my diamond w/prongs broke off my setting. The jeweler drilled out the old prong setting post and put in a new one. There is a yellow like color where the new prong setting was set (ring is platinum) and now my diamond looks quite yellow. Around the prongs, the diamond looks yellow and black. Almost like it was burned. Do you have any idea what might have happened? It was unfortunate enough to almost have lost the entire diamond. Now it looks awful.