snow white n the huntsman - How did Ravenna's mom end up with such insane powers?

Ravenna's mother was supposedly a sorceress, and brought that trait to Ravenna. I am guessing that Finn (Ravenna's brother) did not get that lucky. She probably got the insane powers, one, because she was taught sorcery, and two from her mother. She also could have gotten it from the potion she drank, given to her from her mother before she was taken. I believe Ravenna's mother died because back then, people feared sorcery. They took Ravenna and Finn, thinking the mothers loss of children would make her grow weaker.