She was a member of the Hellfire Club where there she got the name the White Queen. There she gave various attacks on the X-Men. One time she mind controlled the X-Man Storm and made her attack the X-Men. Later she founded the Massachusetts Academy a school for mutants and a rival to Charles Xavier's Institute for Gifted Youngsters. At a point she tried to recruit Shadowcat (Kitty Pryde) but Xavier recruited her first. Her academy is later destroyed and she joins the X-Men where she falls in love with Cyclops (Scott Summers). Then she tries to help Scott find Jean Grey, they find her but she has the spirit of the Phoenix. Then the Hellfire kidnaps Jean and Scott and releases the spirits of the Phoenix but goes on rampage on the city. After that the X-Men rescue Scott and Jean. They go to the city where Jean tries to get the Phoenix to protect the city, but Emma pops out and she gets in, she turns into her diamond form (she could do that) but she isn't powerful enough to hold in so, she shatters. So, in the end she died a heroine she sacrifice herself so Jean could live.
Wolverine and the X-Men
Psychic powers, can turn her skin into diamond but blocks her psychic ability, psychic bolts that can put people into comas