she is a good singer but I would not say that she has the most beautiful voice in the world.
she has a great range and can do a lot of different types of music even though we only hear ballads and r&b.
Mariah Carey has a nice voice, quite unique but I can't stand it when she starts screaming in high pitches. How can anyone sing her songs if she does that... just my personal opinion. She has some good songs too.