Little is known about her functions on Homeworld as of yet, but she seems to be a figure of great authority, similar to Yellow Diamond.
She refers to Sapphire as being of her court, suggesting she has great power and many followers. She was also in charge of colonizing the Earth in the past.
Blue Diamond has a dark navy blue complexion and wears a long, blue cloak of a slightly lighter shade. Her gemstone is located on her chest. She is also noticeably tall in height. This was proven when her Pearl is standing next to her. She has somewhat plump lips and a straight nose
Sapphire was an aristocratic member of Blue Diamond's court. She was valued very highly because of her ability to see into the future.
- Blue Diamond is the first of the Diamonds to be seen in an episode.
- She owns a pearl servant, as does Yellow Diamond.