Maybe your mom was upset that you were shiny. While purple is a beautiful color, shiny silver is more noticeable and attractive in the eyes of most people....
Do you have any psychological issues the family knows about? If you get attention or special treatment due to it perhaps your mom is jelous of the attention you get, or that you feel she feels you should be like her and perhaps not like how you are.. which might be about the psychological problems.

If my mom knew how my mind worked I think she would be mad that I wasn't normal like her...

Just what I happened to interpret, I am no expert so don't take what I say too seriously!

Hope this helps broaden the view though , good luck!