this is graphite, a failed attempt at creating a diamond to fill the void left by pink diamond’s death. she was going to be “repurposed” (read: broken down for parts) but one of her creators took pity on her and spirited her away to an uninhabited planet already gutted for resources
she’s big, but not diamond!big, more like… two jaspers big. she’s kindhearted and lonely, and very forgetful and easily distracted thanks to her damaged gem. she’s slowly wearing away thanks to the soft nature of her gem, and often even leaves smudges of gray on things she touches. one day her gem is going to be too damaged to hold her physical form.
it’s very likely that, should she poof, the force of hitting the ground would be enough to shatter her