Why gems of two types shouldn't fuse

In a time long before the rebellion, when gems were first given their roles, gems of different cuts, courts and types slowly fell in love. They met whenever they had the excuse and made sure no one knew of their romance. When they finally were alone the higher ranking gem took the hand of the smaller being

"there isn't another living thing in sight, let's finally become one." She asked. "I don't think this is a good idea." The lower one replied. "How would anyone find out? It would be between you and me." She said, the smaller gem offered her hand and began to dance,

something went wrong when they combined though, no one knows what caused it. They're gems started to melt together, insuring their eternity together.

The two screamed in agony, waiting for it to stop. When they're form finally set they were in shock, they looked monstrous.

They were forced to go to the luminous and radiant yellow diamond and beg for her help. Even a strong and smart diamond like her couldn't separate the two, she was forced to shatter them. So when you get the urge to fuse, remember this sad tale of two gems and their easily avoidable demise.